We have to prove that Quadrilateral ABCD is a parallelogram.
The third step is m AEB = mCED
As ABCD is a quadrilateral, the point of intersection of diagonals being E.
In the first step while proving it is written that Diagonals bisect each other i.e
AE = EC and BE= ED
After drawing the quadrilateral it is being found that ∠AEB and ∠CED are vertically opposite angles.
Out of the given five options option (D) is the correct option. which is vertical angles theorem.
vertical angle theorem states that if two lines intersect at a point ,then their vertically opposite angles are equal.
