  If you like what you see in Mathguru
Subscribe Today
 For 12 Months US Dollars 12 / Indian Rupees 600 Available in 20 more currencies if you pay with PayPal. Buy Now No questions asked full moneyback guarantee within 7 days of purchase, in case of Visa and Mastercard payment WyzAnt Tutoring

Example: Compare Surface Areas of Spheres

 Post to:   Explanation:

Sphere A two-dimensional perspective projection of a sphere

A sphere (from Greek σφαρα-sphaira, "globe, ball") is a perfectly round geometrical object in three-dimensional space, such as the shape of a round ball. Like a circle in two dimensions, a perfect sphere is completely symmetrical around its center, with all points on the surface lying the same distance r from the center point. This distance r is known as the radius of the sphere. The maximum straight distance through the sphere is known as the diameter of the sphere. It passes through the center and is thus twice the radius.

## Surface area of a sphere

In 3 dimensions, the volume inside a sphere (that is, the volume of a ball) is given by the formula where r is the radius of the sphere and π is the constant pi. (Our solved example in mathguru.com uses this concept)

http://en.wikipedia.org/wiki/Sphere