Question

A cone has volume of 3.

If the cone’s radius is 1, what is its height?

If the cone’s radius is 2, what is its height?

If the cone’s radius is 5, what is its height?

If the cone’s radius is 1/2, what is its height?

Answer 1

r = 1 h = 9

r = 2 h = 2.25

r = 5 h = .36

r = 1/2 h = 36

Explanation:

volume of a cone = ( π * r^2 * h )/ 3

3π = (π * r^2 * h )/3

9π = π * r^2 * h

9 = r^2 * h

h = 9 / r^2

when r is 1 h is 9

when r is 2 -> 9 ÷ 4 = 2.25 = h

when r is 5 -> 9 ÷ 25 = .36 = h

when r is 1/2 -> 9 ÷ 1/4 = 9 * 4 = 36 = h

Answer 2

9/pi or 2.865

2.25/pi or 0.716

9/25pi or 0.115

36/pi or 11.459

Explanation:

The formula for the volume of a cone

V= 1/3pir^2h

V= volume

pi= 3.141592...

r= radius

h= height

1) 3= 1/3pi (1)^2h

9=pi(h)

h= 9/pi or 2.865

2) 3= 1/3pi (2)^2h

9=4pih

h= 9/4pi or 0.716

3) 3= 1/3pi (5)^2h

9= 25pih

h= 9/25pi or 0.115

4) 3=1/3pi (1/2)^2h

9= 1/4pih

h= 36/pi or 11/459