Question

Given the value of cos 25° ≈ 0.9063, enter the sine of a complementary angle. Use an expression relating trigonometric ratios of complementary angles.

cos 25° =___ ° ≈ ____

Answer 1

Cos 25°=Sin65°=0.9063

Explanation:

-Complimentary angles generally refer to the two acute angles of a right triangle.

-The two angles add up to 90º.

Let A and B be the two acute angles. Their trigonometric relationship is such that:

`Sin A\textdegree =Cos \ B\textdegree\\\\Cos \ A\textdegree=Sin \ B\textdegree`

Therefore,

The complementary angle of 25° is 65°

Cos 25°=Sin65°=0.9063