Question

A circle has area of 361pi cm2 what is the circumference in centimeters of the circle

Answer 1

The area of the circle is given as:

$A=\pi r^2$

plugging the value given we have that:

$\begin{gathered} 361\pi=\pi r^2 \\ r^2=361 \\ r=\sqrt[]{361} \\ r=19 \end{gathered}$

Now, the circumference is given as:

$C=\pi d$

where d is the diameter of the circle. The diameter is twice the raidues, hence the diameter is 38, therefore the circumference is:

$C=38\pi$

Therefore the circumference is 38pi