Answer:
A/C
Explanation:
Since the sum of the angles in a triangle equals 180°, and angle C is 90°.
That means angles A and B add up to 90°, that is, they are complementary angles. Therefore the cosine of B equals the sine of A.
We saw on the last page that sin A was the opposite side over the hypotenuse, that is, a/c. Hence, cos B equals a/c.
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