Question 295448: If the radius is 9 inches and the height is 12 inches, what is the approximate surface area of the cone? Answer by Deina(147) (Show Source):
You can put this solution on YOUR website! You didn't specify whether you wanted the total surface area (including the area of the base) or just the lateral surface area, the sides only.
For the lateral surface area of a right cone the formula is , where h is the height of the cone.
For the total surface area of the same cone the formula is , where h is the height of the cone.
Substituting your numbers of r = 9 and h = 12, we get = approximately 339.29 in^2 = approximately 355.29 in^2 & bob's your uncle!
