Table of Contents
Definition
When two lines are crossed by another line (Transversal):
Alternate Interior Angles are a pair of angles on the inner side of each of those 2 lines but on opposite sides of the transversal.
Example
In this example, these are two pairs of Alternate Interior Angles:
c and e
And
d and f
How To remember:
The angle pairs are on Alternate sides of the Transversal, and they are on the Interior of the two crossed lines.
Parallel Lines
When the two lines being crossed are Parallel Lines the Alternate Interior Angles are equal.