if it were a cube thats length was 5 inches, width 3 inches, and height 6 inches i would multiply them all together to get a volume like this, 5 x 3 x 6 which would be 60 in cubed because I multiplied three variables.
Cube- length x width x height Cone-radius squared x Length x 3.14 div. 3 Cylinder- radius squared x length x 3.14 Sphere 4 x 3.14 x radius cubed div. 3
X = multiply Div. = divide Cubed = 5 x 5 x 5 Squared = 5 x 5 Radius= half of the diameter (Diameter is the length across the middle of a circle)
