1. Volume of Spheres

2. Sphere
V = 4/3(π r3)
To calculate the volume of a sphere. 1. Cube the radius
Multiply by 4
Divide by 3
Leave answers in terms of π.

3. Find the volume of the sphere.
V = 4/3 (π r3)
V = 4/3 (π) (23)
V = 4/3 (π) (8)
V = 32/3 (π)
V = 102/3 π ft3

4. Find the volume of the sphere.
V = 4/3 (π r3)
V = 4/3 (π) (73)
V = 4/3 (π) (343)
V = 1372/3 (π)
V = 4571/3 π meters3
Find the radius.
r = 7 m

5. Find the volume of the hemisphere.
A hemisphere is half of a sphere.
To find the volume of a hemisphere you could fine the volume of the sphere and divide by two which is the same as using the formula: V = 2/3(π r3)
V = 2/3 (π) (153)
V = 2/3 (π) (3,375)
V = 6,750/3 (π)
V = 2,250 π in3

6. Work the problem backwards:
The volume of a sphere is 972π in3.
What is the radius of the sphere?
Since we are missing the radius, work the problem backward.
V = 4/3 π r3
972π = 4/3π • r3
729π = πr3
π π
729 = r3
9 = r
Multiply both sides by the reciprocal of 4/3. This would be 3/4.
Divide by π.
Cube root both sides.
The radius of the sphere is 9 in.