Trigonometry 7th Edition

Published by Cengage Learning
ISBN 10: 1111826854
ISBN 13: 978-1-11182-685-7

Chapter 3 - Section 3.1 - Reference Angle - 3.1 Problem Set - Page 122: 19

Answer

- $\frac{1}{2}$

Work Step by Step

To find exact value of $\sin 210^{\circ}$, let's find its reference angle first. As $ 210^{\circ}$ terminates in quadrant III, The reference angle = $ 210^{\circ} - 180^{\circ} $ = $30^{\circ}$ As $ 210^{\circ}$ terminates in quadrant III, its $\sin$ will be negative. Therefore by reference angle theorem- $\sin 210^{\circ}$ = - $\sin30^{\circ}$ = - $\frac{1}{2}$
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.