Answer:
∠ 3 = 93°
Explanation:
∠ 1 and ∠ 2 are vertically opposite angles and are congruent ( equal ), so
∠ 1 = ∠ 2 ( substitute values )
2x - 3 = x + 42 ( subtract x from both sides )
x - 3 = 42 ( add 3 to both sides )
x = 45
Then
∠ 1 = 2x - 3 = 2(45) - 3 = 90 - 3 = 87°
∠ 1 and ∠ 3 are a linear pair and sum to 180° , that is
∠ 1 + ∠ 3 = 180° ( substitute ∠ 1 = 87° )
87° + ∠ 3 = 180° ( subtract 87° from both sides )
∠ 3 = 93°