SOLUTION: The surface area of a ballon varies directly as the square of its radius. The Area is 325 square inches when the radious is 5 inches. What is the surface area when the radius is 9

Algebra ->  Customizable Word Problem Solvers  -> Geometry -> SOLUTION: The surface area of a ballon varies directly as the square of its radius. The Area is 325 square inches when the radious is 5 inches. What is the surface area when the radius is 9       Log On

Ad: Over 600 Algebra Word Problems at edhelper.com


    

Question 868850: The surface area of a ballon varies directly as the square of its radius. The Area is 325 square inches when the radious is 5 inches. What is the surface area when the radius is 9 inches?
Answer by mananth(16946) About Me  (Show Source):
You can put this solution on YOUR website!
+S+%28alpha%29+r%5E2
S=kr%5E2
area 325
r=5
325 =k *5^2
325/25 = k
13=k
r=9
S= 13*9^2
S= 1053 sq.units