ABCD is a cyclic trapezium with AD || BC . If ∠A = 105° , then other three angles are
ABCD is a cyclic trapezium and AD || BC
Sum of angles on the same side of transversal = 180°
=> ∠A + ∠B = 180°
=> ∠B = 180° - 105° = 75°
Also, sum of opposite angles of a cyclic quadrilateral = 180°
=> ∠A + ∠C = 180°
=> ∠C = 180° - 105° = 75°
Similarly, ∠B + ∠D = 180°
=> ∠D = 180° - 75° = 105°
=> Ans - (A)
Create a FREE account and get: