We detail the Circle K cash back policy (including potential limits, fees, and more), plus other gas stations that do cash back. You can typically get up to $40 cash back at Circle...The circumference of a circle is π π times its diameter or 2π 2 π times its radius, where π π is approximately 3.14. C = πd (7.5.1) (7.5.1) C = π d. or. C = 2πr (7.5.2) (7.5.2) C = 2 π r. The symbol π π (Greek letter pi) is standard notation for the number by which the diameter of a circle must be multiplied to get the circumference. Funding Circle the online small business lending platform has partnered with Pitney Bowes to offer small businesses more affordable loans. Funding Circle the online small business ...Wetted Perimeter. Wetted perimeter of a circular channel: P = α D (4b) Hydraulic Radius. Hydraulic radius of a circular channel: R h = D/4 [1 - sin(2 α) / (2 α)] (4c) Hydraulic diameter ; Sponsored Links Related Topics Fluid Mechanics The study of fluids - liquids and gases. ...The perimeter of a semicircle is 1/2 of the circumference of the corresponding complete circle plus the diameter of the circle. The distance around the outside of a semicircle is g...1. Actually, the π is BY DEFINITION, the ratio between the perimeter and the diameter of a circle, from which it follows immediately that perimeter = 2 π r. What you actually have to prove in order to such definition to be correct is that the ratio is the same for all the circles. – jjagmath. Mar 18, 2022 at 20:47.Perimeter of the circular pipe = 2πr = 2 × 3.14 × 4 = 25.12 cm. Perimeter of the square = 4 × Side of the square = 4 × 4 = 16 cm. So, the length of cord left with Pragya = Perimeter of the circular pipe – Perimeter of the square = 25.12 …The circumference of a circle is π π times its diameter or 2π 2 π times its radius, where π π is approximately 3.14. C = πd (7.5.1) (7.5.1) C = π d. or. C = 2πr (7.5.2) (7.5.2) C = 2 π r. The symbol π π (Greek letter pi) is standard notation for the number by which the diameter of a circle must be multiplied to get the circumference. The perimeter of a circle can be calculated using the formula C = 2πr and the area can be calculated using the formula A = πr², where r is the radius of the circle. In this article, we will learn about the perimeter and area of a circle in detail. We will learn about its formulas and apply them to solve some practice problems. Feb 8, 2024 · The term perimeter refers either to the curve constituting the boundary of a lamina or else to the length of this boundary. The perimeter of a circle is called the circumference, although that term is used by some authors to refer to the perimeter of an arbitrary curved geometric figure. The perimeter of a region is implemented in the Wolfram Language as Perimeter[reg]. The perimeters of some ... When a=b, the ellipse is a circle, and the perimeter is 2πa (62.832... in our example). When b=0 (the shape is really two lines back and forth) the perimeter is 4a (40 in our example). They all get the perimeter of the circle correct, but only Approx 2 and 3 and Series 2 get close to the value of 40 for the extreme case of b=0.An inscribed angle of a circle is an angle whose vertex is a point \(A\) on the circle and whose sides are line segments (called chords) from \(A\) to two other points on the circle. In Figure 2.5.1(b), \(\angle\,A\) is an inscribed angle that intercepts the arc \(\overparen{BC} \). We state here without proof a useful relation between ...Some good Target Circle Offers have gone out that can save you a nice chunk of money. They appear to be working on some gift cards too. Increased Offer! Hilton No Annual Fee 70K + ...Find the perimeter of a circle using its radius or diameter, or vice versa. Learn the formula, see examples and FAQs, and explore other circle calculators.Learn how to calculate the circumference (perimeter) of a circle using different formulas and values. Use the calculator to enter any one value and get the others, or explore related measures such as radius, diameter and area. Learn how to calculate the circumference of a circle using the formula C = 2πr or C = πd, where r is the radius or diameter of the circle. Find out the meaning, methods and examples of circumference and area of a circle. Also, explore the formulas for semi-circles and other shapes. Authentic Circle is the loyalty program at Miraval Resorts & Spas, a luxury, adults-only, all-inclusive Hyatt brand that focuses on wellness. We may be compensated when you click o...Twitter have introduced a new feature called Twitter Circle, which will be a new way to Tweet to a smaller audience. Twitter have introduced a new feature called Twitter Circle, wh...An easy to use, free perimeter calculator you can use to calculate the perimeter of shapes like square, rectangle, triangle, circle, parallelogram, trapezoid, ellipse, octagon, and sector of a circle. Formulas, explanations, and graphs for each calculation. Perimeter of a triangle calculation using all different rules: SSS, ASA, SAS, SSA, etc.5 days ago · A circle is the set of points in a plane that are equidistant from a given point O. The distance r from the center is called the radius, and the point O is called the center. Twice the radius is known as the diameter d=2r. The angle a circle subtends from its center is a full angle, equal to 360 degrees or 2pi radians. A circle has the maximum possible area for a given perimeter, and the ... Authentic Circle is the loyalty program at Miraval Resorts & Spas, a luxury, adults-only, all-inclusive Hyatt brand that focuses on wellness. We may be compensated when you click o...Learn how to find the perimeter (or circumference) of a circle using the formula C = π d, where C is the circumference and d is the diameter. Practice with free printable worksheets and online quiz on perimeter of a …'AMC Comes Full Circle' is now playing in an equity market near you, writes technical analyst Ed Ponsi, who says movie theater operator AMC Entertainment Holdings (AMC) saw...Question 1: For a vehicle having wheels of radius 24cm find the distance covered by it in one complete revolution of wheels. Answer: Distance covered by wheel in one complete revolution = circumference of wheel=Perimeter of Circle= 2πR. Here, R=24cm. Distance covered = 2x (22/7)x24. Java program to calculate or to print area of a circle in a simple method.If you were new to java or at the beginning stage then, Check – 500+ simple Java programs for beginners. The following Java program to print the area of a circle has been written in five simple different ways, static method, using constructor, Interface, inheritance with …When Croatia became the 28th member of the European Union on July 1, it indelibly changed the shape of the group. When Croatia became the 28th member of the European Union on July ...Learn how to find the radius, diameter, and circumference of a circle using formulas and examples. The circumference of a circle is equal to pi times the diameter, or pi times the …Paver walkways and patios are popular DIY projects. Use fast-setting concrete for edging to contain the pavers along the perimeter. Expert Advice On Improving Your Home Videos Late...What is circumference. The circumference is the perimeter of a circle or an ellipse. Generally, the perimeter is defined as the length of the curve around any closed figure. However, the term "perimeter" is conventionally used to describe the distance around the boundary of a polygon. The term "circumference" is specific to circles and ellipses.Paver walkways and patios are popular DIY projects. Use fast-setting concrete for edging to contain the pavers along the perimeter. Expert Advice On Improving Your Home Videos Late...The circumference of a circle is basically the distance around a circle. For example, if you had a park or other outdoor area that was shaped in a perfect circle, and you walked all the way around the edge of it, you would have walked along the circumference of the circle. Basically, you can think of the circumference as the perimeter of a circle.Jan 18, 2024 · To calculate the radius of a circle, divide its circumference by 2π; for the circle's diameter, divide the circumference by π. Let's say that the circumference of a given circle is 20 inches. Therefore, its radius is 3.18 in, and its diameter is 6.37 in. Calculate the diameter of a circle with this tool. A circular pipe with height 5 m and diameter 7 m has a central angle of. θ = cos -1 ( 1 - ( 5 / 3.5 ) ) = cos -1 ( -1.5 / 3.5 ) = 2.01371 Radians. Wetted Perimeter = 2.01371 x 7. = 14.096. The perimeter of the wet cross sectional area is known as the wetted perimeter. It depends on the hydraulic diameter or hydraulic radius.Area of a Circle Formula. The area of a circle is the total amount of space enclosed by its boundary or circumference. There is no volume in a circle because it is a flat, two-dimensional shape. If you know the radius of a circle, you can easily find its area. As you can see, the radius of the circle is just the line segment from the center to ...Perimeter or Circumference of a circle = π · d where: d is the diameter of the circle Area of the Circle Formula Area of the circle = π · r ² where: r is the radius of the circle π is Pi, approximately (up to 3 decimals) 3.142Learn how to find the circumference and area of a circle using the formulae \\ (C = \\pi d\\) and \\ (A = \\pi {r^2}\\). See examples, video summaries and practice questions on …4 days ago · You can calculate it as follows: If you know the radius or diameter of the circle, the area of the circle formula is: a = πr² = π × (d / 2)². If radius and diameter are unknown, you can calculate it from the circumference: a = c² / 4π. If you are interested in calculations of some fraction of a circle, check: Jul 3, 2019 · The circumference of a circle is its perimeter or distance around it. It is denoted by C in math formulas and has units of distance, such as millimeters, centimeters, meters, or inches. The circumference of a circle is the measured total length around a circle, which when measured in degrees is equal to 360°. 1. Actually, the π is BY DEFINITION, the ratio between the perimeter and the diameter of a circle, from which it follows immediately that perimeter = 2 π r. What you actually have to prove in order to such definition to be correct is that the ratio is the same for all the circles. – jjagmath. Mar 18, 2022 at 20:47.Examples of the Perimeter of a Circle Calculation from the Radius or Diameter. Pi equivalent to approximately 3.14159, let us take the example of a circle having a radius of 4cm: Perimeter = (4 x 2) x π. Perimeter = 8 x π. Perimeter = 25.13. Let us reproduce the example with a circle with a diameter of 11 cm: Perimeter = 11 x π. Perimeter ...We turn to our smart phones to findtrendy restaurants, dress for the weather, and check in on our friends’ latest adventures. For some people, leaving the house sans iPhone or Andr...Having a thriving community is the backbone for creators, but when the global pandemic hit, brands also found that they needed similar engagement with customers that were now inter...The area of a sector with a central angle α = 90° of a circle with radius r = 1 is π/4. To calculate this result, you can use the following formula: A = r² · α/2, substituting: r = 1; and. α = 90° · π/180° = π/2. Thus: A = (1² · π/2)/2 = π/4. Notice that this is also a quarter of the area of the whole circle.An inscribed angle of a circle is an angle whose vertex is a point \(A\) on the circle and whose sides are line segments (called chords) from \(A\) to two other points on the circle. In Figure 2.5.1(b), \(\angle\,A\) is an inscribed angle that intercepts the arc \(\overparen{BC} \). We state here without proof a useful relation between ...We turn to our smart phones to findtrendy restaurants, dress for the weather, and check in on our friends’ latest adventures. For some people, leaving the house sans iPhone or Andr...Perimeter of a Parallelogram (with side, height, and angle), P = 2a + 2h / sin θ, where a is the side, h is the height, and θ is the angle; Perimeter Formula of a Circle The perimeter formula of a circle consists of two main components - 2 constants and one radius of theAug 3, 2023 · Sector of a Circle Formula. Let us solve some examples to understand the concept better. The length of an arc is 64 mm. Find the area of the sector formed by the arc if the circle’s radius is 15 mm. Solution: As we know, Area (A) of a sector = r × L/2, here r = 15 mm, L = 64 mm. = (15 × 64/2) mm 2. = 480 mm 2. What is A Circumference of a Circle? The circumference of a circle measures the total length of the boundary. In other words, the length of the circular path of a circle is its circumference. A circle is a two-dimensional shape that has area and perimeter. The circumference, also known as the circle's perimeter, is measured in …Find the exact circumference of the circle. Answer \(9.1 \pi\) in. Practice Set B. Find the approximate circumference of the circle. Answer. 5.652 mm. Practice Set B. Find the approximate circumference of the circle with radius 20.1 m. Answer. 126.228 m. Practice Set B. Find the approximate outside perimeter of . Answer. 41.634 mmA circle is a round plane figure with a boundary (called the circumference) that is equidistant from its center. It is a fundamental object studied in geometry. In order to describe the shape of an object, we give the object appropriate dimensions. For example, a rectangle can be described with its height and width. It is harder to describe the shape of …The perimeter of a semicircle is 1/2 of the circumference of the corresponding complete circle plus the diameter of the circle. The distance around the outside of a semicircle is g...Unit test. Test your understanding of Area and perimeter with these % (num)s questions. Area and perimeter help us measure the size of 2D shapes. We’ll start with the area and perimeter of rectangles. From there, we’ll tackle trickier shapes, such …PSA: Do not post your deepest darkest secrets on your Twitter Circle. It might surface on your Followers' For You timeline. PSA: Do not post your deepest darkest secrets on your Tw...Example 1: Finding circumference when given diameter. Find the circumference of a circle with a diameter of 3 . The formula for the circumference of a circle that uses diameter is: C = π d. C = π 3. C = 3 π. We can stop here and write our answer as 3 π . Or we can plug in 3.14 for π and multiply. C = 3.14 ⋅ 3.The equation for the area of a circle is: A = π r 2. A = π ⋅ 8 2. A = π ⋅ 64. We can stop here and write our answer as 64 π . Or we can plug in 3.14 for π and multiply. A = 3.14 ⋅ 64. A = 200.96 square units. The area of the circle is 64 π square units or 200.96 square units.Some good Target Circle Offers have gone out that can save you a nice chunk of money. They appear to be working on some gift cards too. Increased Offer! Hilton No Annual Fee 70K + ...A brand-new funding partnership has been launched that aims to improve access to vital capital and business insurance resources for small business owners in the United States. A br...Answers for perimeter of circle (13) crossword clue, 13 letters. Search for crossword clues found in the Daily Celebrity, NY Times, Daily Mirror, Telegraph and major publications. Find clues for perimeter of circle (13) or most any crossword answer …The circumference is equal to 2 times 5 times the radius. So it's going to be equal to 2 times pi times the radius, times 3 meters, which is equal to 6 meters times pi or 6 pi meters. 6 pi meters. Now I could multiply this out. Remember pi is just a number. Pi is 3.14159 going on and on and on. Funding Circle the online small business lending platform has partnered with Pitney Bowes to offer small businesses more affordable loans. Funding Circle the online small business ...Learn how to calculate the circumference of a circle using the formula C = 2πr or C = πd, where r is the radius or diameter of the circle. Find out the meaning, methods and examples of circumference and area of a circle. Also, explore the formulas for semi-circles and other shapes. A few important parts of a circle are given below. Circumference: It is also referred to as the perimeter of a circle and can be defined as the length of the boundary of the circle. Radius of Circle: Radius is the distance from the center of a circle to any point on its boundary. A circle has an infinite number of radii. Enter any value of a circle parameter and get the remaining ones using the formula πR^2. Learn the definitions and formulas of circle parts, such as center, radius, diameter, …11 Dec 2017 ... An example of how to find the area and perimeter of a circle that's missing a quarter of it's area. Use the area and circumference formulas, ...The area and perimeter worksheets on this page start with requiring students to calculate area and perimeter of basic shapes such as triangles, squares, circles and ellipses. An additional set of worksheets includes examples of area nad perimeter problems for a mix of primitive shapes. Additional worksheets with compound shapes require students ...Using the perimeter of a circle formula, The perimeter of the circle or circumference = 2π r. 2 π r = 110. 2 × 22/7 × r = 110. r = 110 × 7 / 44. r = 17.5. Answer: Radius of circle = 17.5 in. Example 3: The radius of a circle is 7 in. Using the perimeter of a circle formula, calculate the circle’s circumference. Let's break the area into two parts: Part A is a square: Area of A = a 2 = 20m × 20m = 400m 2. Part B is a triangle. Viewed sideways it has a base of 20m and a height of 14m. Area of B = ½b × h = ½ × 20m × 14m = 140m 2. So the total area is: Area = Area of A + Area of B = 400m 2 + 140m 2 = 540m 2. Sam earns $0.10 per square meter.Jul 20, 2023 · Download Article. 1. Use the formula C = πd to find the circumference if you know the diameter. In this equation, "C" represents the circumference of the circle, and "d" represents its diameter. That is to say, you can find the circumference of a circle just by multiplying the diameter by pi. Plugging π into your calculator will give you its ... What is circumference. The circumference is the perimeter of a circle or an ellipse. Generally, the perimeter is defined as the length of the curve around any closed figure. However, the term "perimeter" is conventionally used to describe the distance around the boundary of a polygon. The term "circumference" is specific to circles and ellipses.The circumference of a circle and the area of a circle have one thing in common: the radius. If I were you I'd do it in two steps: - first calculate the radius using the circumference formula, - then calculate the area using the radius you just calculated :-) Hope that helps! d = diameter. C = circumference. A = area. π = pi = 3.1415926535898. √ = square root. Use this circle calculator to find the area, circumference, radius or diameter of a circle. Given any one variable A, C, r or d of a circle you can calculate the other three unknowns. Units: Note that units of length are shown for convenience.The perimeter of a circle is called the circumference. To find the circumference, we use the formula C = π d , C = π d , where d d is the diameter, the distance across the center, or C = 2 π r , C = 2 π r , where r r is the radius.Feb 8, 2024 · The term perimeter refers either to the curve constituting the boundary of a lamina or else to the length of this boundary. The perimeter of a circle is called the circumference, although that term is used by some authors to refer to the perimeter of an arbitrary curved geometric figure. The perimeter of a region is implemented in the Wolfram Language as Perimeter[reg]. The perimeters of some ... A circle is a geometric figure with all points at an equal distance from a central point. This distance is referred to as the radius. A circle is defined by its center (o) and radius (r). It can also be defined by its area and perimeter, calculated as follows: Area of a circle = πr^2. Perimeter of a circle = 2πr.These are the formulas to calculate the circumference and area of a circle: c = 2πr A = πr² = πd²/4, where: c stands for circumference;; r for radius; and; d for the diameter of the circle.; π is a constant approximately equal to 3.14159265359 and, among other things, represents the circumference-to-diameter ratio of any circle.There's been lots of conversation lately about whether or not Google+ is a "ghost town." If you're wondering the same, let us prove it's no such thing: add the Lifehacker Google+ p...The radius of a circle is 12 cm. Using the perimeter of a circle formula, calculate the circumference of the circle. Solution: To find: Perimeter of a circle. Given: r = 12 cm. The perimeter of circle formula = 2 π r. C = 2 × (22/7) × (12) C= 75.4 cm. Answer: The circumference of a circle is 75.4 cm. When a=b, the ellipse is a circle, and the perimeter is 2πa (62.832... in our example). When b=0 (the shape is really two lines back and forth) the perimeter is 4a (40 in our example). They all get the perimeter of the circle correct, but only Approx 2 and 3 and Series 2 get close to the value of 40 for the extreme case of b=0.An easy to use, free perimeter calculator you can use to calculate the perimeter of shapes like square, rectangle, triangle, circle, parallelogram, trapezoid, ellipse, octagon, and …Example 3: A circle has a radius of 5.2 cm Calculate the area of the circle. To find the area of a circle we use the formula: Area = π r 2. We need to substitute 5.2 in for r: Area = π (5.2) 2. We can now type this into a calculator which gives us the answer of: 676 ⁄ 25 π. The radius was given in cm, and we measure area in squares, so the ...A brand-new funding partnership has been launched that aims to improve access to vital capital and business insurance resources for small business owners in the United States. A br...5 days ago · A circle is the set of points in a plane that are equidistant from a given point O. The distance r from the center is called the radius, and the point O is called the center. Twice the radius is known as the diameter d=2r. The angle a circle subtends from its center is a full angle, equal to 360 degrees or 2pi radians. A circle has the maximum possible area for a given perimeter, and the ... Find the circumference of the circle in the following figure if the length of the side of the square is 30cm. Assume . A semi-circular table mat is to be bordered with a diamond lace that costs Rs. 80 per meter. What would be the cost of the lace if the radius of the mat is 20 cm? Take . Find the perimeter of the following shape. Assume .Determine the perimeter of a hexagon by adding the length of its 6 sides. If it is a regular hexagon, where the lengths of all sides are equal, the perimeter can also be determined...Perimeter is the distance around a two-dimensional shape. Example: ... The perimeter of a circle is called the circumference: Circumference = 2 ... Determining tangent lines: lengths. Proof: Segments tangent to circle from outside point are congruent. Tangents of circles problem (example 1) Tangents of circles problem (example 2) Tangents of circles problem (example 3) Challenge problems: radius & tangent. Challenge problems: circumscribing shapes. A circle is the set of points in a plane that are equidistant from a given point O. The distance r from the center is called the radius, and the point O is called the center. Twice the radius is known as the diameter d=2r. The angle a circle subtends from its center is a full angle, equal to 360 degrees or 2pi radians. A circle has the maximum possible …The equation for the area of a circle is: A = π r 2. A = π ⋅ 8 2. A = π ⋅ 64. We can stop here and write our answer as 64 π . Or we can plug in 3.14 for π and multiply. A = 3.14 ⋅ 64. A = 200.96 square units. The area of the circle is 64 π square units or 200.96 square units. 1) Radius of the circle is perpendicular to point of contact between the tangent and the circle. 2) Tangents drawn from an external point of the circle are of equal length. 3) Tangents drawn from an external point are equally inclined to the line segment joining the external point and centre of the circle. 4) Tangents drawn at the endpoints of ...
When a=b, the ellipse is a circle, and the perimeter is 2πa (62.832... in our example). When b=0 (the shape is really two lines back and forth) the perimeter is 4a (40 in our example). They all get the perimeter of the circle correct, but only Approx 2 and 3 and Series 2 get close to the value of 40 for the extreme case of b=0.. Mtu housing
Circumference = π × diameter = 2 π × radius. In geometry, the circumference (from Latin circumferens, meaning "carrying around") is the perimeter of a circle or ellipse. [1] The circumference is the arc length of the circle, as if it were opened up and straightened out to a line segment. [2] More generally, the perimeter is the curve length ... In order to compute the area and the perimeter of a circle of radius r r we use the following formulas: \text {Perimeter} = 2\pi r Perimeter = 2πr \text {Area} = \pi r^2 Area = πr2. Computationally speaking, it is really simple to compute the area and the perimeter of a circle, by simply plugging the radius r r in the above formulas.A circular sector, also known as circle sector or disk sector or simply a sector (symbol: ⌔ ), is the portion of a disk (a closed region bounded by a circle) enclosed by two radii and an arc, with the smaller area being known as the minor sector and the larger being the major sector. [1] In the diagram, θ is the central angle, the radius of ...The perimeter of a circle divided by its diameter is known as pi. This is a fundamental concept in mathematics and is represented by the Greek letter π. Pi is an irrational number, approximately equal to 3.14159, which is the ratio of a circle's circumference to its diameter.Examples of the Perimeter of a Circle Calculation from the Radius or Diameter. Pi equivalent to approximately 3.14159, let us take the example of a circle having a radius of 4cm: Perimeter = (4 x 2) x π. Perimeter = 8 x π. Perimeter = 25.13. Let us reproduce the example with a circle with a diameter of 11 cm: Perimeter = 11 x π. Perimeter ... Perimeter Formulas The perimeter of any polygon is the sum of the lengths of all the sides. Note: "ab ... Examples. square = 4a. rectangle = 2a + 2b triangle = a + b + c . circle = 2pi r . circle = pi d (where d is the diameter) The perimeter of a circle is more commonly known as the circumference. Units. Be sure to only add similar units. For ...The circumference of a circle is the measurement of how far the distance goes around the circle. We can think of it as the “perimeter” of the circle because it is literally the measure of the length of the circle’s boundary. So if you have a circle made up of a piece of thread and you cut it, and you measure its length using a straight ...Learn how to calculate the perimeter of a circle using the formula 2 x π x radius or π x diameter. Find the definition, examples and differences between a circle and a disc.For example, the circumference of a circle with a radius of 4 inches is simply 2 x 3.14159 x 4 = 25.13 inches. If the diameter is given instead, first divide it by two, then repeat the above process. For example, if the diameter is 16 feet, then the radius is 16 / 2 = 8 feet. The circumference is therefore 2 x 3.14159 x 8 = 50.26 feet. Basic geometry and measurement 14 units · 126 skills. Unit 1 Intro to area and perimeter. Unit 2 Intro to mass and volume. Unit 3 Measuring angles. Unit 4 Plane figures. Unit 5 Units of measurement. Unit 6 Volume. Unit 7 Coordinate plane. Unit 8 Decomposing to find area.Circle object c1 with radius= 4.5 Area = 63.62 Perimeter = 28.27 Circle object c1 with radius= 9.2456 Area = 268.55 Perimeter = 58.09 Second Execution Circle object c1 with radius= 2.54 Area = 20.27 Perimeter = 15.96 Circle object c1 with radius= 5.26 Area = 86.92 Perimeter = 33.05Learn how to calculate the circumference or perimeter of a circle using different formulas based on radius, diameter or area. …Circle object c1 with radius= 4.5 Area = 63.62 Perimeter = 28.27 Circle object c1 with radius= 9.2456 Area = 268.55 Perimeter = 58.09 Second Execution Circle object c1 with radius= 2.54 Area = 20.27 Perimeter = 15.96 Circle object c1 with radius= 5.26 Area = 86.92 Perimeter = 33.05Enter any value of a circle parameter and get the remaining ones using the formula πR^2. Learn the definitions and formulas of circle parts, such as center, radius, diameter, …To calculate the radius of a circle, divide its circumference by 2π; for the circle's diameter, divide the circumference by π. Let's say that the circumference of a given circle is 20 inches. Therefore, its radius is 3.18 in, and its diameter is 6.37 in. Calculate the diameter of a circle with this tool..