Compute the surface area of the portion of the cone z=sqrt(x^2+y^2) below the plane z=4. (Answer: 16pi*sqrt(2))
You can use geometry to get the answer.
r = 4, h = 4
slant height = sqrt(r^2 + h^2) = 4sqrt(2)
lateral area of a cone
= (1/2)perimeter of the base * slant height
= (1/2) (2pi*4) (4sqrt(2)) = 16pi*sqrt(2)