## Basic College Mathematics (9th Edition)

The unknown angle is 67$^{\circ}$.
The sum of the angle in a Triangle is 180$^{\circ}$. Here we will solve for the unknown angle. We will label it $X$. Therefore: 180$^{\circ}$ = 46$^{\circ}$ + 67$^{\circ}$ + $X$ $X$ = 180$^{\circ}$ - (46$^{\circ}$ + 67$^{\circ}$) $X$ = 180$^{\circ}$ - (113$^{\circ}$) $X$ = 67$^{\circ}$