Geometry: Common Core (15th Edition)

Published by Prentice Hall
ISBN 10: 0133281159
ISBN 13: 978-0-13328-115-6

Chapter 8 - Right Triangles and Trigonometry - Chapter Test - Page 537: 18

Answer

$\angle A \approx 13.0^{\circ}$

Work Step by Step

In this exercise, we are given the measure of a non-included angle and two sides. We can use the law of sines to find the measure of another angle in the triangle. The law of sines states the following: $\frac{sin A}{\overline{BC}}$ = $\frac{sin B}{\overline{AC}}$ = $\frac{sin C}{\overline{AB}}$, where $A$, $B$, and $C$ are the measures of the angles in the triangle and $\overline{BC}$, $\overline{AC}$ and $\overline{AB}$ are the measures of the sides opposite those angles, respectively. Let's plug in what we know into the formula: $\frac{sin 72}{38}$ = $\frac{sin \angle A}{9}$ Multiply each side by $9$: $\frac{sin 72}{38}(9)$ = sin $\angle A$ Take sin$^{-1}$ of both sides to solve for $\angle A$: $\angle A \approx 13.0^{\circ}$
Update this answer!

You can help us out by revising, improving and updating this answer.

Update this answer

After you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.