All GRE Math Resources
Example Question #4 : Spheres
Find the surface area of a sphere with a diameter of 14. Use π = 22/7.
Surface Area = 4πr2 = 4 * 22/7 * 72 = 616
Example Question #1 : Spheres
A sphere has a surface area of square inches. If the radius is doubled, what is the surface area of the larger sphere?
Cannot be determined
The surface area of the larger sphere is NOT merely doubled from the smaller sphere, so we cannot double to find the answer.
We can use the surface area formula to find the radius of the original sphere.
r2 = 4
r = 2
Therefore the larger sphere has a radius of 2 * 2 = 4.
The new surface area is then square inches.
Example Question #1 : How To Find The Surface Area Of A Sphere
If a sphere has a volume of cubic inches, what is its surface area?
The volume of a cube is equal to .
So we mutiply our volume by and divide by , giving us .
The surface area of a sphere is equal to , giving us .