#### Answer

$28.6^{\circ} $

#### Work Step by Step

We use the Law of Cosines to find:
$cos(2\alpha)= \frac{-(6^2) + 5^2 + 7^2 }{2(5)(7)} \\ cos2\alpha = .54 \\ \alpha = 28.6^{\circ} $

Published by
Cengage

ISBN 10:
978-1-337-61408-5

ISBN 13:
978-1-33761-408-5

$28.6^{\circ} $

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