Posted by Piggy on .
The surface area of a cone is 38 in^2. The radius of a similar cone is triple the radiusof the orginal cone. What is the surface area of the new cone?

geometry 
MathMate,
Similar cones have area proportional to the square of the linear dimensions.
So if the new cone has three times the radius, the area is 3²=9 time that of the original cone.