# How to figure out the circumference of a circle?

#### Understand the Problem

The question is asking for the method to calculate the circumference of a circle. The circumference is the distance around the circle, and it can be calculated using the formula C = 2πr, where r is the radius of the circle.

C = 2πr

To figure out the circumference of a circle, you need to use the formula C = 2πr, where C is the circumference, π (pi) is approximately 3.14159, and r is the radius of the circle.

#### Steps to Solve

1. Identify the formula

The formula for the circumference of a circle is:

$C = 2πr$

Where:

• C is the circumference
• π (pi) is approximately 3.14159
• r is the radius of the circle

Measure or identify the radius of the circle. The radius is the distance from the center of the circle to any point on its edge.

2. Apply the formula

Substitute the values into the formula and calculate:

3. Multiply the radius by 2

4. Multiply the result by π (3.14159)

For example, if the radius is 5 units:

$C = 2 × π × 5$ $C ≈ 2 × 3.14159 × 5 ≈ 31.4159$ units

To figure out the circumference of a circle, you need to use the formula C = 2πr, where C is the circumference, π (pi) is approximately 3.14159, and r is the radius of the circle.