(The diameter is twice the radius, the length from any point on the circle to its center.) **If you divide the circumference of the circle by the diameter, you will get approximately 3.14**—no matter what size circle you drew!

Radius of a circle is **the distance from the center of the circle to any point on it's circumference**. It is usually denoted by 'R' or 'r'. This quantity has importance in almost all circle-related formulas. The area and circumference of a circle are also measured in terms of radius.

To calculate the circumference of a circle, **multiply the diameter of the circle with π (pi)**. The circumference can also be calculated by multiplying 2×radius with pi (π=3.14).

(The diameter is twice the radius, the length from any point on the circle to its center.) **If you divide the circumference of the circle by the diameter, you will get approximately 3.14**—no matter what size circle you drew!

Diameter is defined as the length of a straight line through the center of a circle. An example of a diameter is **the length of a line sliced down the center of a pie**.

**How to Use a Measuring Tape for Diameter**

- Find the center of a circular area and mark it in some way.
- Secure a tape measure anywhere on the circle and pull the tape measure to a point on the opposite side of the circle.
- Measure just the radius of the circle if it is very large.

In basic mathematics, pi is used **to find the area and circumference of a circle**. Pi can be used to find an area by multiplying the radius of the circle squared times pi. So, to find the area of a circle with a radius of 3 centimeters, the calculation would be π3^2 = 28.27 cm.

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Let “r” be the radius of the circle. Hence, the radius of the circle = 7 cm.

Question 4: Find the radius of the circle whose circumference is 22 cm.

More topics in Radius Formula | |
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Unit Circle Formula | Circle Formula |

Diameter Formula | Surface Area of a Sphere Formula |

The circumference of a circle is equal to pi times the diameter. The diameter is two times the radius, so the equation for the circumference of a circle using the radius is **two times pi times the radius**.

A line segment that crosses the circle by passing through its center is called **a diameter**. The diameter is twice the length of the radius.

**The Radius is the distance from the center outwards.** **The Diameter goes straight across the circle, through the center**. The Circumference is the distance once around the circle.

**How to Calculate Diameter?**

- Diameter = Circumference ÷ π (when the circumference is given)
- Diameter = 2 × Radius (when the radius is given)
- Diameter = 2√ (when the area is given)

Divide the area (in square units) by Pi (approximately 3.14159). Take the square root of the result (Example: 310.56). This is the radius. Now double the radius to get the diameter (Example: 621.12 meters).

Diameter of a Circle

Diameter is **the full length of the circle running from the edge, through the midpoint, all the way to the other side**. That is this whole length right here. The diameter of a circle is represented by the letter d.

Just **divide the circumference by π** to find the diameter. For example, if your circle has a circumference of 23 inches, the diameter would be 23/π, or approximately 7.32 inches. If you only know the area of the circle, use the formula diameter = 2 x √(area/π).

1 : **a straight line that runs from one side of a figure and passes through the center** Measure the diameter of the circle. 2 : the distance through the center of an object from one side to the other : thickness the diameter of a tree trunk. diameter. noun.

Dated : 03-Jul-2022

Category : Education