difference between alt interior angles and alt exterior angles
Alternative interior angle
When a line (called a transversal) intersects a pair of parallel lines alternative interior angles are fo he Alternate Interior Angles Theorem states that
When two parallel lines are cut by a transversal, the resulting alternate interior angles are congruent. 
rmed. Alternate interior angles are equal to each other.
Alternative exterior angle
One way to remember alternate exterior angles is that they are the vertical angles of the alternate interior angles. Alternate exterior angles are equal to one another.
The Alternate Exterior Angles Theorem states that
When two parallel lines are cut by a transversal, the resulting alternate exterior angles are congruent.
