Question

A sphere with a diameter of 16 mm has the same surface area as the total surface area of a right cylinder with the base diameter equal to the sphere diameter. How high is the cylinder? A. 8 mm B. 14 mm C. 18 mm D. 16 mm

Answer 1

Surface of the sphere = 4*pi*r^2 = 256pi

Surface of cylinder = 2pi*r*h + 2pi*r^2 = 256pi
pi*r*h + pi*r^2 = 128pi
pi*8*h + 64pi = 128pi
8h = 64
h = 8