#### What is a transversal?

**Answer:**
A transversal is a line, like the red one below, that intersects two other lines.

Typically, the intercepted lines like * line a *and *line b* shown above above are parallel, but they do not have to be.

#### What is so special about a transversal?

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

### Interior and Exterior Regions

### The Congruent Angle Pairs

There are 3 types of angles that are congruent: Alternate Interior, Alternate Exterior and Corresponding Angles.

#### Can you make a Z?

A way to help identify the alternate interior angles.

Some people find it helpful to use the 'Z test' for alternate interior angles.

If you can draw a Z or a 'Backwards Z' , then the alternate interior angles are the ones that are in the corners of the *Z*

##### Problem 1

$$ \angle$$D and $$ \angle$$W

$$ \angle$$X and $$ \angle$$C

##### Problem 2

$$ \angle$$A and $$ \angle$$Z

$$ \angle$$Y and $$ \angle$$B

##### Problem 3

$$ \angle$$A and $$ \angle$$W

$$ \angle$$D and $$ \angle$$Z

$$ \angle$$X and $$ \angle$$B

$$ \angle$$C and $$ \angle$$Y

### The Supplementary Angle Pairs

There are 2 types of supplementary angles that are formed: same side interior and same side exterior.

**Interactive** Parallel Line and Angles

∠GEH | 90 | ∠EFI | 90 |
---|---|---|---|

∠HEF | 90 | ∠IFN | 90 |

∠OEF | 90 | ∠NFL | 90 |

∠GEO | 90 | ∠LFE | 90 |