• Home

Surface Area of a Sphere

The Greek mathematician Archimedes discovered that the surface area of a sphere is the same as the lateral surface area of a cylinder having the same radius as the sphere and a height the length of the diameter of the sphere.

The lateral surface area of the cylinder is $2\pi rh$ where $h=2r$ .

 Lateral Surface Area of the Cylinder $=2\pi <mi>\; r\; </mi>\; (2r)=4\pi r^2$ .

Therefore, the Surface Area of a Sphere with radius $r$ equals $4\pi r^2$ .