Q1 of 33 Page 95

By calculating let us write the angles of the parallelogram ABCD, when ∠B = 60°.

Given ABCD is a Parallelogram so ∠ABC = ∠ADC (opposite angles of Parallelogram are equal)


⇒ ∠ABC = ∠ADC = 60°


Also, BC ∥ AD and AB is transversal


⇒ ∠ABC + ∠DAB = 180° (angles on the same side of transversal)


⇒ ∠DAB = 180° - 60° = 120°


⇒ ∠DCB = 120° (opposite angles of Parallelogram are equal)


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