In many cases, factoring an expression can make it easier to evaluate as in the following...

In many cases, factoring an expression can make it easier to evaluate as in the following applications.

Spherical shells: The volume of a spherical shell (like the outer shell of a cherry cordial) is given by the formula , where R is the outer radius and r is the inner radius of the shell. Write the right-hand side in completely factored form, then find the volume of a shell where R = 1.8 cm and r= 1.5 cm. Answer in exact form and in approximate form rounded to the nearest tenth.