Question

a circle has a radius of 10 inches. the circumference of the circle is c inches. which expression best represents the value of π?
a 10c
b $\frac{c}{10}$
c $\frac{c}{20}$
d 20c

Explanation:

Step1: Recall circle - circumference formula

The formula for the circumference of a circle is $c = 2\pi r$, where $c$ is the circumference and $r$ is the radius.

Step2: Substitute given radius value

Given $r = 10$ inches, so $c=2\pi\times10 = 20\pi$.

Step3: Solve for $\pi$

Rearrange the equation $c = 20\pi$ to get $\pi=\frac{c}{20}$.

Answer:

C. $\frac{c}{20}$