SOLUTION: Find the radius of the base of each cylinder if the surface area is 425.1 square feet, and the height is 6.8 feet.

Algebra ->  Surface-area -> SOLUTION: Find the radius of the base of each cylinder if the surface area is 425.1 square feet, and the height is 6.8 feet.      Log On


   

Question 136477This question is from textbook
: Find the radius of the base of each cylinder if the surface area is 425.1 square feet, and the height is 6.8 feet. This question is from textbook

Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
Find the radius of the base of each cylinder if the surface area is 425.1 square feet, and the height is 6.8 feet.
:
Surface area of a cylinder formula:
SA = %282%2Api%2Ar%5E2%29+%2B+%282%2Api%2Ar%2Ah%29
:
In this problem:
%282%2Api%2Ar%5E2%29+%2B+%282%2Api%2Ar%2A6.8%29 = 425.1
:
%282%2Api%2Ar%5E2%29+%2B+%2813.6%2Api%2Ar%29 - 425.1 = 0
:
Multiply the numerical values, 2 and 13.6 by pi, treat it like a quadratic eq:
6.283r%5E2+%2B+42.725r+-+425.1+=+0
Solve for r using the quadratic formula: a = 6.283; b = 42.725; c = -425.1
:
You should get a positive value of r = 5.5 ft