Question

Given sin28.4=.4756, cos28.4=.8796, and tan28.4=.5407 find the cos of 61.6

Answer 1

cos 61.6 = .4756

Explanation:

Imagine a right-angled triangle.

The two other angles other than the right angle sum up to 90°, right?

Then 61.6° + 28.4° = 90°, so put those two angles in each of the vertices

You will realize that the cos of 61.6° is the sin of 28.4°

Answer 2

0.4756

Explanation:

The sine of any acute angle is equal to the cosine of its complement. The cosine of any acute angle is equal to the sine of its complement.

Meaning that sin 28.4 = cos 61.6

since 28.4+61.6=90 degree