Question

A balloon has a circumference of 22 in. Use the circumference to approximate the surface area of the balloon to the nearest square centimeter.

Answer 1

Balloons don't have a circumference.

Answer 2

you need to use the circumference to find the radius...

\[C=2\pi r\]

\[22 = 2\pi r\]

\[\frac{22}{2\pi} = r\]

\[r \approx 3.5\]

next the surface area of a sphere is

\[SA = 4\pi r^2\]

JUts substitute r and evaluate