The total surface area of a cone is the sum of the area of its base and the lateral (side) surface.

So:Area of a cone = (area of the base) + (area of the side) = (pi)r^2 + (pi)(r)(l)

Recall that the area of a circle (the base) is π*r*^{2 }and you add that to the lateral area (side of the cone) which is π*rl *in this case.

A = π(15)^2 + π(15)(11) = 225π + 165π = **390****π units^2**.