Answer:
5. angle A=40
6. angle C= 80
7. angle C= 110
Explanation:
In all three questions, it says angle B= angle A+ angle C
So for each when it gives you angle B and one of the others, you just subtract either angle A or angle C from the total angle (B) to find the other. For example, for question 5, it asks for angle A saying that B is a right angle and c equals 50. Well, a right angle is 90 degrees. So to find angle A, you do 90-50.