Are adjacent angles in a parallelogram supplementary?
Yes adjacent angles of a parallelogram are supplementary
Proof,
Let us consider Parallelogram.
To prove:
We have, and is a transversal.
We know that interior angles on the same side of a transversal are supplementary.
Therefore,
Similarly,
Therefore, the sum of any two adjacent angles of a parallelogram is equal to .
Hence, it is proved that any two adjacent or consecutive angles of a parallelogram are supplementary