Parallel Lines, a Transversal and the angles formed. Corresponding, alternate exterior, same side interior...

When a transversal cuts (or intersects) parallel lines several pairs of congruent and supplementary angles are formed.

Interactive Parallel Line and Angles

Click and Drag Points E and F to explore the relationship of corresponding, alternate interior and alternate extior angles that are formed by a transversal and parallel lines. (Full Size Version)

Congruent Angle Pairs

Listed below are the types of congruent angles formed by parallel lines.

Line X is parallel to line Y

Picture parallel lines cut by transversal

Corresponding Angles:

1 and

4 and

2 and

3 and

Alternate Exterior Angles

1 and

2 and

Alterrnate Interior Angles

3 and

4 and

Supplementary Angles
Same Side Interior angles

3 and

4 and

Line P is parallel to line v

Angles Formed by Parallel Lines and Transversal

Identify the corresponding angles below
corresponding angles
alternate exterior angles alternate interior

same side interior

Parallel Lines cut by a Transversal

Angles formed

Interactive Parallel Line and Angles

Line X is parallel to line Y

Line P is parallel to line v