Welcome to MooMooMath. Today we are going to talk to parallel lines cut by transversals. First of all we have two parallel lines over here. Line M and line N and they are drawn in blue and they are parallel to each other which means that don’t touch each other. Then we have this green line and we will call it line L and it is what we will call a transversal. It is a line that intersects both parallel lines. Now it c creates several relatiionships of angles. This video will touch on just one of these relelationships. Say we are given this angle.( Points to angle at the top) and angle one is 70 degrees and I will label the angle 70 degrees. We can figure out angle 2 and angle 3. Angle 2 is a vertical angle to angle one so that means that measure of angle two is also 70 degrees because vertical angles are congruent to each other. Now let’s look at angle three. Angle three is a linear pair with angle two. We know the measure of lines add up to 180 so if this angle is 70 the angle three will be it’s supplement so take 180 and subtract 70 and that equals 110 degrees. So angle three will be 110 degrees. Angle 1 and three are supplementary, angles two and three are also supplementary because angles 1 and angle 2 are congruent to each other so hope this video was helpful.

The angle measure of these angles are congruent.

In this picture angles <**1** and <**4 **and <**2 **and <**3** are linear pairs. The angle measure of linear pairs equals 180 degrees.

In this example <**2** and < **6** and <**5** and <**3** are **alternate interior angles**

In this example <**1** and < **8** and

<**4** and <**7** are **alternate exterior angles**

In this example <4 and< 6,<**3** and<**8, **<**1** and <**5,** and <**2** and<**7** are **corresponding angles**

Transversal

In Geometry what are the properties of the angles created by transversals? A transversal is a line that intersects two or more lines that can be parallel. The transversal creates several angles. These angles are given "names" that describe their location and properties. The following is a list of names with illustrations describing the angles created by transversals, as well as several theorems.

Three terms that will help with your understanding of angles related to transversals.

If the lines that are intersected by the transversal are parallel, then corresponding angles are equal measure. If the lines are not parallel, then there is no relationship between the angles.

Angles 1 and 8 are alternate exterior angles, and angles **3** and **5** are alternate interior angles.