Q27 of 100 Page 17

ABCD is a cyclic trapezium with AD||BC. If ∠B=70°, determine other three angles of the trapezium.

Given that,

ABCD is a cyclic trapezium with AD ‖ BC and ∠B = 70o


Since, ABCD is a quadrilateral


Then,


∠B + ∠D = 180o


70o + ∠D = 180o


∠D = 110o


Since, AD ‖ BC


Then,


∠A + ∠B = 180o (Co. interior angle)


∠A + 70o = 180o


∠A = 110o


Since, ABCD is a cyclic quadrilateral


Then, ∠A + ∠C = 180o


110o + ∠C = 180o


∠C = 70o


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