The measure of the four successive angles of a quadrilateral are in the ratio 7 : 11 : 7 : 11. The quadrilateral is a ______.
1). trapezium
2). rectangle
3). parallelogram
4). square
From the given ratio we can see that angles be 7y, 11y, 7y and 11y
We can see that alternate angles are equal and two consecutive angles are supplementary.
∴ The quadrilateral is a parallelogram.
6. In which of the following quadrilaterals opposite angles are supplementary?