How do u do this? ! show me how
part a and b especially b!

Check the picture below.

in the picture below, the bottom part

notice, 69° + 21° = 90°, so 21° and 69° are really complementary angles, sharing the same quadrant, meaning for any two sides of lengths say, a,b one angle will have a tangent of say b/a, then the other will have a tangent of a/b.

namely the tangent of each angle, is simply the other's tangent upside-down.

answer: what statements

step-by-step explanation if you write the statements down then i could you.