Answer:
90
Step-by-step explanation:
Angles 2 and 3 are complementary; this means that they sum 90 degrees. You know that they are complementary because the 2 non-right angles in a right triangle always sum to 90. This makes sense because all triangles equal 180 and one of the angles is 90 degrees; therefore, the others must equal 90. In this case, angles 1 is 90 degrees because it forms a linear pair with a 90-degree angle.
