Question

A quadrilateral ABCD is a parallelogram if

• A. AB = CD
• B. AB // CD
• C. ∠A = 50° ,∠C = 50° ,∠B =130°
• D. AB⊥AD

Answer 1

The correct option is D

AB⊥AD

(A) If opposite sides of a quadrilateral are parallel,it is a parallelogram.

(B) If opposite sides of a quadrilateral are equal,then by congruency we can prove that both pairs of opposite sides are parallel and hence a parallelogram.

(C) If one pair of opposite sides of a quadilateral are equal and parallel, then by congruency we can prove that the other pair of opposite sides are parallel and hence a parallelogram.