Answer:
x = 60°
Explanation:
∠ ABO and ∠ CBO are a linear pair and sum to 180° , that is
∠ ABO + ∠ CBO = 180°
150° + ∠ CBO = 180° ( subtract 150° from both sides )
∠ CBO = 30°
∠ XYO and ∠ CBO are alternate angles and are congruent , so
∠ XYO = 30°
∠ XOY and ∠ COY are a linear pair and sum to 180° , then
∠ XOY + ∠ COY = 180°
∠ XOY + 90° = 180° ( subtract 90° from both sides )
∠ XOY = 90°
the sum of the 3 angles in Δ XOY = 180° , that is
x + 90° + 30° = 180°
x + 120° = 180° ( subtract 120° from both sides )
x = 60°