6.Two adjacent angles of a parallelogram have equal measure. Find the measure of each of the angles of the parallelogram.

Let ABCD be a parallelogram in which we have, ∠A = ∠B

We know \(∠A + ∠B = 180^{\circ}\quad\) [Sum of adjacent angles = \(180^{\circ}\)]

\(∠A + ∠A = 180^{\circ}\)

\(\Rightarrow 2∠A = 180^{\circ}\)

\(\Rightarrow ∠A = 90^{\circ}\)

Thus, \(∠A =∠C = 90^{\circ} and ∠B = ∠D = 90^{\circ}\quad \) [Opposite angles of a parallelogram are equal]