parallel lines cut by a transversal, corresponding angles, anternate interior angles, alternate exterior angles

$Class Table$

Parallel Lines and Angles Cut by a Transversal

Page and Other Contents: Vertical Pairs of Angles; Adjacent Supplementary Angles; Names for the Matched Angles
corresponding angles,
alternate interior angles,
alternate exterior angles; Play with angles THAT MOVE and remeasure!

A Line Crosses A Pair of Parallel Lines

If a set of 2 parallel lines, line l and line m, are crossed or cut by another line, line n, we say "a set of parallel lines are cut by a transversal."
Each of the parallel lines cut by the transversal has 4 angles surrounding the intersection.
These are matched in measure and position with a counterpart at the other parallel line.
At each of the parallel lines, there are two pairs of vertical angle. Each angle in the pair is congruent to the other angle in the pair.: 1 4, angle 1 is congruent to angle 4.; 2 3, angle 2 is congruent to angle 3.; 5 8, angle 5 is congruent to angle 8.; 6 7, angle 6 is congruent to angle 7.

Adjacent Supplementary Angles

At each of the parallel lines adjacent angles are supplementary.

Names for the Matched Angles

The angles have special names identifying their positions with respect to the parallel lines and transversal.
They are corresponding angles, alternate interior angles, or alternate exterior angles.
An angles is congruent to its matched angle.