Posted by John on .
The surface area of acone with height 15 cm is 500π square cm. Find the radius of the cone. Round your answer to two decimal places.

Geometry 
Mgraph,
The surface area
SA=Pi*r^2+Pi*r*s, s=sqrt(r^2+h^2)
500*Pi=Pi*r^2+Pi*r*sqrt(r^2+225)
500=r^2+r*sqrt(r^2+225)
500r^2=r*sqrt(r^2+225)
(500r^2)^2=(r*sqrt(r^2+225))^2
2500001000r^2+r^4=r^2(r^2+225)
250000=1225r^2
r^2=250000/1225