A wooden frame has screws at A, B, C, and D so that the sides of it can be pressed to change the angles occurring at each vertex. ABCD and AB || CD, even when the angles
change. Why is the frame always a parallelogram?
D
None of the other answers are correct
One pair of opposite sides is congruent and parallel, so ABCD is a parallelogram.
One pair of opposite sides is congruent, so ABCD is a parallelogram.
All sides are congruent, so ABCD is a parallelogram.
The angles always stay the same. so ABCD is a parallelogram.