Q: 12 Prove that a cyclic parallelogram is a rectangle.
Given: ABCD is a cyclic quadrilateral.
To prove: ABCD is a rectangle.
Proof :
In cyclic quadrilateral ABCD.
.......................1(sum of either pair of opposite angles of a cyclic quadrilateral)
........................................2(opposite angles of a parallelogram are equal )
From 1 and 2,
We know that a parallelogram with one angle right angle is a rectangle.
Hence, ABCD is a rectangle.