How do you find the volume of a sphere?

Find the volume of a sphere by solving for the equation V=4/3*pi*r^3, where V is volume, r stands for radius and pi is 3.1459. Cube the radius, and multiply that number by pi and 4/3 for the volume. Pi delineates the relationship between a circle's diameter and circumference.

1. Simplify the equation

   Make the equation simpler by inserting 3.1459 for pi and multiplying that figure by 4/3. This creates a value of approximately 4.19453. Now, your equation is V=4.19453*r^3, or the radius cubed times 4.19453.

2. Input the variables

   Replace the variables of the equation with the numbers related to the sphere. For instance, a sphere with a radius of 5 inches means the volume is 4.19453 times 5^3. Five cubed is five times five times five, or 125.

3. Solve the formula

   Multiply 125 by 4.19453 to get 524.3167 cubic inches of volume in a sphere with a radius of five inches. You can convert cubic inches to cubic feet by multiplying the volume by 0.000579 to get 0.30358 cubic foot.

4. Change the volume

   Increase or decrease the diameter of a sphere to change the volume. When a sphere changes its diameter by just one inch, the volume changes by 142 cubic inches. If the diameter of this sphere shrinks from 10 inches to 9 inches, the volume is 382.2 cubic inches.