Question

The area of a circle is 320 square meters. Find the radius of the circle. Then find the circumference. Round your answers to the nearest tenth.

Answer 1

Radius = 10.1 m

Circumference = 63.4 m

Explanation:

Area = 3.14 × r²

320 = 3.14 × r²

r² = 101.9108280255

r = 10.0950893025

Circumference = 2 × 3.14 × r

= 2 × 3.14 × 10.0950893025

= 63.3971608197

Answer 2

10.1 m =r

C = 63.4 m

Explanation:

We know the area of a circle is given by

A = pi r^2 where pi can be approximated by 3.14 and r is the radius

320 = 3.14 r^2

Divide each side by 3.14

320/3.14 = 3.14 r^2/3.14

101.910828 = r^2

Take the square root of each side

sqrt(101.910828) =sqrt( r^2)

10.0950893 = r

To the nearest tenth 10.1 =r

Now we want the circumference

C = 2*pi*r

C =2 *3.14 *10.1

C =63.428

To the nearest tenth

C = 63.4