Use the CAST diagram to determine which quadrant is the cos B in. After determining your quadrant, since cos = ADJ/HYPO, you can fill in the values of the triangle as shown. I have provided the solution for question 1. The rest of the questions follow the same operation. Hope it helps!

*How to know cos B is in the 1st Quadrant?*

It is given that cos B = p/2 , notice it is positive? Hence, it can only be either in the 1st or 4th quadrant.

To choose between these two, look at the other information given = ACUTE. Hence, cos B has to be in the 1st quadrant.