Circumference =
18 ÷ 2 = 9
r = 9
-----------------------------------------------------------------------------------------------------------------
Area =
=
= 81 units².
Answer:
D 81 pi units^2
Step-by-step explanation:
The circumference of a circle is given by
C = 2 * pi *r
18 pi = 2 * pi *r
Divide each side by 2 * pi
18 pi / (2 pi) = 2 pi * r/ (2 pi)
9 = r
Now we can find the area. Area is given by
A = pi r^2
A = pi * 9^2
A = 81 pi units^2
Answer
D
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