In this section, we looked at how to solve application problems that use polynomials. Below are some of the formulas that were used to solve these problems.

## Key Concepts

**Perimeter**= Sum of the Length of the Sides of a Figure**Area of a Rectangle**[latex]A=lw[/latex]**Area of a Circle**[latex]A=\pi{r^2}[/latex]**Volume of a Cylinder**[latex]V=\pi{r^2}h[/latex]**A Note about [latex]\pi[/latex]**It is easy to confuse [latex]\pi[/latex] (pronounced “pie”) as a variable because we use a greek letter to represent it. We use a greek letter instead of a number because nobody has been able to find an end to the number of digits of [latex]\pi[/latex].**Profit**is typically defined in business as the difference between the amount of money earned (revenue) by producing a certain number of items and the amount of money it takes to produce that number of items.- [latex]P=R-C[/latex] where [latex]P[/latex] is profic, [latex]R[/latex] is the revenue generated by selling those items, and [latex]C[/latex] is the cost to a manufacturer to produce a certain number of items.