Hotmath
Math Homework. Do It Faster, Learn It Better.

Sphere

A sphere is the set of all points in space at a given distance from a given point. The given distance is called the radius and the given point is the center.

Half of a sphere is called a hemisphere .

 

The surface area of a sphere is 4 π times the square of the radius.  ( S . A . = 4 π r 2 )

Example 1:

Find the surface area of a sphere with a radius of 11 cm.
S . A . = 4 π ( 11 ) 2 = 484 π cm 2 .

The volume of a sphere is four-thirds pi times the cube of the radius.  ( V = 4 3 π r 3 )

Example 2:

Find the volume of a sphere with a radius 2 cm.

V = 4 3 π ( 2 ) 3 = 32 π 3 cm 3 33.51 cm 3