Question: abcd is a quadrilateral and bd is a diagonal?
Answer: Given: ABCD is a quadrilateral and BD is one of its diagonals. To Prove: ABCD is a parallelogram and to determine its area. ... Given: The side AB of a parallelogram ABCD is produced to any point P. A line through A and parallel to CP meets CB produced at Q and then parallelogram PBQR is completed.