Sunday, September 11, 2011

Parallel Lines: The Different Pairs of Angles

Note: This is more of a review for myself...

When two parallel lines are cut by a transversal line, eight angles will be formed, like this:

In such a situation, you can identify four types of angle pairings: alternate exterior angles, alternate interior angles, corresponding angles, and same-side interior angles.

Alternate Exterior Angles

1 and 8 are also alternate exterior angles
Alternate exteriors angles are equal to each other.

Alternate Interior Angles (Z-pattern)

4 and 5 also form the z-pattern
Alternate interior angles are also equal to each other.

Corresponding Angles (F-pattern)

(2,6),  (3,7) and (1,5) also form the f-pattern
Corresponding angles are also equal to each other.

Same-Side Interior (C-pattern)

3 and 5 also form c-pattern
Same-side interior angles are supplementary (they add up to 180 degrees).

Yes... that's it. Not much explanation.