Chapter 2 - Solving Equations - 2-5 Literal Equations and Formulas - Practice and Problem-Solving Exercises - Page 113: 42

The polygon has 9 sides.

In order to answer the problem, you must use the formula provided and plug in the polygons interior angle of 1260 for "s", and answering for "n" afterward. $s=180(n-2)$ $1260=180(n-2)$ $(1260)/180=(180)/180(n-2)$ $7=1(n-2)$ $7=n-2$ $7+2=n-2+2$ $9=n$