Question

A right triangle in which one acute angle is a reference angle for a 75° angle in standard position intersects the unit circle at (0.259,0.966). What is the approximate value of cos75°

Answer 1

Alright, lets get started.

Please take a look at the diagram attached.

The reference angle of 75 will be 75

As it is mentioned that the angle intersects the unit circle means r = 1

So, finding cos

cos 75 = $\frac{X}{r}$

cos 75 = $\frac{0.259}{1}$

cos 75 = 0.259    :   Answer

Hope it will help :)