Question

What's the circumference of acircle with a diameter of 9 inches?Use 3.14 for T.C = [?] inches

Answer 1

Given a cricle with radius "r", the diameter "d" is related by:

$\begin{gathered} d=2r \\ r=\frac{d}{2} \end{gathered}$

For this circle, the circumference can be calculated by:

$c=2\pi r$

We have d = 9 in and π = 3.14. So:

$r=\frac{9}{2}=4.5$$c=2\pi r=2\cdot3.14\cdot4.5=28.26$

So, the circumference is 28.26 in.