A student wishes to prove that quadrilateral is a parallelogram

MATHEMATICS · Single correct · CBSE · Mathematics · Quadrilaterals · Quadrilaterals

Problem

A student wishes to prove that quadrilateral

ABCD

is a parallelogram. Which one of the following single statements, if known to be true, is by itself adequate for the proof? (a)

\angle A + \angle B = 180^{\circ}

(b)

\angle A = \angle D

(c)

\angle A = \angle C \,\text{and}\, \angle B = \angle D

(d)

\angle A + \angle C = 180^{\circ}