Question

A balloon has a circumference of 28 in. Use the circumference to approximate the surface area of the balloon to the nearest square inch.

784 in2

2,463 in2

998 in2

250 in2

Answer 1

Hi there,

Using Surface Area = 4 x pi x r^2

Circumference = 2 x pi x r

28 = 2 x pi x r

28/2 x pi = r

radius = 4.5ins

Surface Area = 4 x pi x 4.5^2

Surface Area = 254.5 ins^2

Surface Area = 255 ins^2 (to nearest square inch)