Answer:
7.
This is a complementary angle, which means that the two angles add up to 90 degrees. The two angles, in this case, are b and 52. Thus, we have:
b + 52 = 90
b = 38.
Therefore, b is 38 degrees.
8. This is a supplementary angle, which means that the two angles add up to 180 degrees. There is a right angle in the picture to confuse us, so we can just pretend that that doesn't exist, and just focus on the 180-degree angle (which is the straight line). The two angles shown are b and 117, so we have:
b + 117 = 180
b = 63
Therefore, b is 63 degrees.
9. This is a supplementary angle, which means that the two angles add up to 180 degrees. There is another line in the picture to confuse us, so we can just pretend that the line that is making a triangle (the one opposite of 125 degrees) doesn't exist, and just focus on the 180-degree angle (which is the straight line). The two angles shown are b and 125, so we have:
b + 125 = 180
b = 55
Therefore, b is 55 degrees.