If the radius of a sphere increases from 3 feet to 9 feet, by how many cubic feet does the volume of the sphere increase?

3 cubic feet

Step-by-step explanation:

3²=9

936pi (approx. 2940)

Step-by-step explanation:

Volume of a sphere = (4/3) * pi*r³

V1 with r = 3 ft

V1 = (4/3) * pi*3³ = 36pi

V2 with r = 9ft

V2 = (4/3) * pi*9³ = 972pi

Increase = 972pi - 36pi = 936pi ft³

Which is approximately 2940 ft³ correct to 3 significant figures