Trigonometry 7th Edition

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

Chapter 7 - Section 7.2 - The Law of Cosines - 7.2 Problem Set - Page 378: 24

Answer

$a =122.88 \hspace{1pt}km$ $B=25.111^\circ$ $C=30.222^\circ$

Work Step by Step

$a^2 = b^2+c^2-2ac \cos{A^\circ} \\= (63.4)^2+(75.2)^2-2 \times 63.4 \times 75.2 \cos{124.667^\circ}= 15098$ $$a = \boxed{122.88 \hspace{1pt} km}$$ $\cos{B} = \dfrac{a^2+c^2-b^2}{2ac} = \dfrac{(122.88)^2+(75.2)^2-(63.4)^2}{2 \times 122.88 \times 75.2} = 0.9055$ $$\therefore B =\boxed{25.111^\circ} $$ $$C = 180-(A+B) = 180-(124.667+25.111) = \boxed{30.222^\circ}$$
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.