Question

A spherical balloon has a circumference of 21 cm. What is the approximate surface area of the balloon to the nearest square inch?

Answer 1

Answer:140 cm^2

Explanation:

The answer is D. 140 cm². I think the circumference of the balloon means the circumference of the biggest circle. So the 21=2πr². While the surface area of a sphere is S=4πr². So the S≈140 cm².