Question

What is the area of a circle that has a circumference of 42 inches? A. 140.4 in2 B. 126.60 in2 C. 132.62 in2 D. 21.04 in2

Answer 1

Circumference = 2 $\pi$ r
                   42  = 2 $\pi$ r
42/(2 $\pi$) = r
21/$\pi$ = r

Area = $\pi$ r²
         = $\pi$ (21/$\pi$)²
         = 21²/$\pi$
         = 140.37
         ≈ 140.4

Answer: A