line p and line q are parallel

Line r is a transversal

See how <4, <5, <6 and <3 are "inside"?

These are interior angles, between the parallel lines

See how <1, <2, <8 and <7 are "outside"

These are exterior angles, outside of the parallel lines

The red angles are corresponding angles

They have the same measure and are in the same position

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​Corresponding angles are congruent

The Orange Angles are Alternate Exterior

They are conguent

Aqua Angles are Alternate Interior

They are conguent

Purple angles are same side exterior

They are supplementary

Yellow Angles are Vertical

Vertical angles are congruent

Green angles are same side interior

Same Side Interior Angles are supplementary