Question

A cylindrical water tank has a diameter of 9 feet and a height of 16 feet. Each can of paint covers 50 square feet. What is the minimum number of cans of paint needed to cover the outside of the tank

Answer 1

12 cans

Explanation:

The area of the outside of the tank:

radio = half diameter = 4.5 ft.

base:
`A_(b) =\pi r^(2) =\pi (4.5)^(2) =20.25\pi`

Top: = base
`=20.25\pi`

cylinder:
`2\pi rh=2\pi (4.5)(16)=144\pi`

Total area to paint:
`144\pi +2(20.25\pi) =184.5\pi =579.6sq.ft.`

Number of cans of paint:

`c=(579.6)/(50) =11.59=12`

Hope this helps