In: Advanced Math
Let K be a cone with a circular bottom, that has a radius r, and the apex is directly above the center of the bottom. Let h represent the height of the cone. Show that the surface area of the cone K without the bottom is equal to
pi * r * sqrt(r^2 + h^2) .
(Use that a sector that is given with angle θ in a circle with radius R has the area (θ * R^2)/2