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

Okay so use the surface area = 4x pi x r^2

circumference = 2x pi x r

28 = 2x pi x r

28/2x pi = r

radius = 4.5 ins

surface area = 4x pi x 4.5^2

surface area = 254.5 ins^2

surface area = 255 ins^2 (to the nearest square inch)