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Trigonometry
Trigonometric ratios: Cosine

Cosine: The cosine of an angle in a right triangle equals the adjacent side divided by the hypotenuse.

 cos θ = adj hyp

 Find Cos A and Cos B
Using the Pythagorean Theorem, the missing leg must be 15, then
 Cos A = 15 17 and Cos B = 8 17

Look at the following right triangle, where:
a = 4
b = 5
Find the cosine of angle A

The cosine of angle A s =
(round the solution to hundredths)