Question

What is the approximate circumference of a circle with a radius of 20 inches? Use π ≈ 3.14. A. 125.6 inches B. 251.2 inches C. 120 inches D. 62.8 inches

Answer 1

C = pi*d = 2*pi*r
C = 2*pi*20 = 3.14*40 = 125.6in

A

Answer 2

For any circle, the circumfrence
`C=2\pi r=\pi d` where r is the radius and d is the diameter.
Use 20 inches for our radius in the formula
`C=2\pi r`.

`C=2\pi *20`
Using π ≈ 3.14...

`C\approx2*3.14*20`

`C\approx6.28*20`

`\boxed{C\approx125.6\ inches}`