Q9 of 100 Page 17

In a cyclic quadrilateral ABCD if AB||CD and B=70°, find the remaining angles.

Given that,

∠B = 70o


Since, ABCD is a cyclic quadrilateral


Then,


∠B + ∠D = 180o


70o + ∠D = 180o


∠D = 110o


Since, AB ‖ DC


Then,


∠B + ∠C = 180o (Co. interior angle)


70o + ∠C = 180o


∠C = 110o


Now,


∠A + ∠C = 180o (Opposite angles of cyclic quadrilateral)


∠A + 110o = 180o


∠A = 70o


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