Answer:
Explanation:
A parallelogram is a quadrilateral with congruent opposite sides and pair of opposite angles.
Given: parallelogram ABCD
AD≅ BC
AD ║ BC
Thus;
<ABC + DAB =
(supplementary angle property)
ΔABD = ΔCBD (each diagonal divides a parallelogram into two congruent triangles)
<ABC = <ADC (both pairs of opposite angles are congruent)
<DAB = <BCD (both pairs of opposite angles are congruent)
AB ≅ CD (opposite sides are congruent)
AB ║ DC (pair of opposite sides are parallel)
Therefore, the quadrilateral ABCD is a parallelogram.