8th Grade · Geometry
Alternate Interior Angles
8.G.A.5
Definition
A pair of angles between two lines and on opposite sides of a transversal. When the lines are parallel, these angles are equal.
Examples
- If one alternate interior angle is 65°, the other is also 65°.
- They form a Z-pattern between parallel lines.
Key rule
With parallel lines, alternate interior angles are always equal.
Memory hook
Inside the lines, opposite sides, equal angles.