Question

find the radius and circumference of the circle below: d = 36 ft
check the box for the radius and for the circumference below.
9ft
36π
36ft
18π
18ft
9π

Explanation:

Step1: Find the radius

The radius $r$ of a circle is half of the diameter $d$. Given $d = 36$ ft, so $r=\frac{d}{2}$.
$r=\frac{36}{2}=18$ ft

Step2: Find the circumference

The formula for the circumference $C$ of a circle is $C = 2\pi r$ or $C=\pi d$. Using $C = \pi d$ with $d = 36$ ft, we get $C = 36\pi$ ft. Using $C = 2\pi r$ with $r = 18$ ft, we also get $C=2\pi\times18 = 36\pi$ ft.

Answer:

Radius: 18 ft
Circumference: $36\pi$ ft