Question

A spherical water tank has a diameter of 42 feet. How much water can the tank hold when full?

A) 10,561π cubic feet

B) 12,348π cubic feet

C) 15,934π cubic feet

D) 21,568π cubic feet

Answer 1

We know that the radius is 21 by dividing the diameter by half

volume of a sphere is v = $\frac{4}{3} \pi r^3$

$v= \frac{4}{3} \pi 21^3=12,348[tex] \pi$ [/tex]

Answer is B

Answer 2

This problem asked us to compute for the volume of the tank. The shape of the tank is a sphere. Hence the volume of the sphere is (4/3) of pi times the cube of the radius. Radius is twice the diameter. Since the diameter is 42 feet the radius is 21 feet. Given this we can already find the volume. The volume is 
V = (4/3)pi(r^3) = pi(4/3)(21^3) = pi(4/3)(9216) = pi(12348) = 12,348pi ft.^3