Question

Can someone help me?

Answer 1

Answer:

Step-by-step explanation:

If arccos (√3 / 2) = β, then cos β = adjacent side / hypotenuse = √3 / 2.  This tells us immediately that the adjacent side length is √3 and the hypotenuse is 2.  Via the Pythagorean Theorem, we know that the third side is 1.  

This information rules out the 1st and 3rd answer choices.

Because cos 30° = adj / hyp = √3 / 2, we can conclude that the correct answer is the 4th one:  30°, 60°, 90°