SOLUTION: If 1 gallon of paint covers 400 square feet, about howmany gallons of paint are needed to paint the outside of a sperical tank of diameter 20 feet?

Algebra ->  Customizable Word Problem Solvers  -> Geometry -> SOLUTION: If 1 gallon of paint covers 400 square feet, about howmany gallons of paint are needed to paint the outside of a sperical tank of diameter 20 feet?       Log On

Ad: Over 600 Algebra Word Problems at edhelper.com


    

Question 206148: If 1 gallon of paint covers 400 square feet, about howmany gallons of paint are needed to paint the outside of a sperical tank of diameter 20 feet?
Answer by Marth(57) About Me  (Show Source):
You can put this solution on YOUR website!
The surface area of a sphere is found by SA=4%2Api%2Ar%5E2
Given that the diameter is 20ft, the radius is 20%2F2=10ft


The surface area is therefore SA=4%2Api%2A10%5E2 = 400%2Api square feet.
Divide that by 400ft per gallon of paint, and you need pi gallons of paint, which is around 3.14.