52 I think , because 6 1/2 x 8 is 52
A because complementary angles means 2 angles that add together to equal 90 degrees and it's possible for both angles to be 45.
B because it juss makes sense
15 times 2 = 30
20 times 2 = 40
40 + 30 = 60
60 / 6 = 10
so the answer will be 10
