Question

A cone has a volume of 108 pi and a base diameter of 12. What is the height of the cone?

Answer 1

Answer:

h  = 9 units of length

Step-by-step explanation:

Volume of a circular right cone is:

V(c)  = (1/3)*Area of the circular base * h

Where h is the height of the cone, then

V(c)  =  (1/3) * π * r² * h

And  we have that  V(c) = 108*π

Then:

108 * π  =  (1/3) * π * r² * h                  (1)

We know diameter of the circular base is 12 units, according to that

r =  d/2     ⇒  r = 12/2     r = 6 units

Then:

108 * π  [ cubic units ]  =  (1/3) * π * (6)² * h  [square units] [ units of length]

When simplifying we have to take into account that in order to keep last equation h needs to have units of length  

Therefore:

108  =  (1/3) * 36 * h

h = ( 108* 3 )/ 36

h  = 9 units of length