Question

Anyone know the answer to this geometry problem?

Answer 1

Let's talk about the choices
◯  ∠4 and ∠5 . . . . . . . . these are complementary angles whose sum is 90°
◯  ∠7 and ∠9 . . . . . . . . these are vertical angles, equal to each other
◯  ∠2 and ∠3 . . . . . . . . these are supplementary angles that together form a straight line. They are a linear pair.
◯  ∠1 and ∠2 . . . . . . . . these are "adjacent" angles in the quadrilateral that also includes ∠9 and ∠10.

The appropriate choice is ...
  ◉  ∠2 and ∠3