## Geometry: Common Core (15th Edition)

$\angle$ ABC = 135 $^{\circ}$
The equation to find the measure of a single angle in any given polygon with n number of sides is $\frac{180(n-2)}{n}$. $\angle$ ABC is red and is therefore part of the larger, red shape. This shape has 8 sides. Therefore, plug 8 into the equation and solve. $\frac{180(n-2)}{n}$ $\frac{180(8-2)}{8}$ $\frac{180(6)}{8}$ $\frac{1080}{8}$ = 135 $^{\circ}$