## Elementary Geometry for College Students (7th Edition)

$y = 13.1$ units
1. Find $\angle C$ $\angle C = 180 - (60 + 40)$ $=180 - 100$ $= 80^{\circ}$ 2. Use the sine law to find $y$ $\frac{y}{sin(40)} = \frac{20}{sin(80)}$ $y = \frac{20sin(40)}{sin(80)}$ by GDC / calculator $y = 13.0540...$ units $y = 13.1$ units