Answer:
A , D , B , B
Explanation:
(9)
a and b form a right angle , that is a + b = 90°
angles which sum to 90° are complementary
the answer is then A
(10)
b and 110° lie on a straight line and are a linear pair which sum to 180°
b + 110° = 180° ( subtract 110° from both sides )
b = 70° → D
(11)
5x + 3 and 73 are vertically opposite angles and are congruent (equal) , so
5x + 3 = 73 ( subtract 3 from both sides )
5x = 70 ( divide both sides by 5 )
x = 14 → B
(12)
x and y are alternate interior angles and are congruent
These angle pairs are on opposite (alternate) sides of the transversal and are in between ( in the interior of ) the parallel lines