In the given diagram,
∠O'OB and ∠OO'P are called
A simple way to identify alternate interior angles is to remember that it appears on the alternate sides of the transversal and on the interior of the other two lines.
∠O'OB and ∠OO'P are alternate interior angles as they lie on alternate sides of transversal XY and on interior sides of AB and PQ.
Therefore, ∠O'OB and ∠OO'P will be alternate interior angles.