Question

1. The area of a circle is 314.2 square feet. What is the length of its radius?

A 10 ft
C 31.4 ft
B 20 ft
D 62.8 ft

Answer 1

10 ft

Explanation:

The area of a circle is given by

A = pi r^2

314.2 = pi r^2

Let pi be approximated by 3.142

314.2 = 3.142 r^2

Divide each side by 3.142

314.2/3.142 = 3.142 r^2/3.142

100 = r^2

Take the square root of each side

sqrt(100) = sqrt(r^2)

10 =r