A line that crosses two parallel lines is called a transversal. For example, the line in the diagram below is a transversal.
A pair of parallel lines with a transversal form a set of angles, shown below.
This set of eight angles can be grouped into two categories:
- We have four pairs of vertical angles:
- We also have four pairs of so-called corresponding angles:
Corresponding pairs of angles are located in the same position as each other relative to the parallel lines and on the same side of the transversal. Pairs of corresponding angles are congruent.
Consider the following pair of parallel lines and the transversal
What is the value of
First, note that and are corresponding angles. Therefore, they are congruent and thus have the same measure. This means we can write down the following equation:
To solve this equation, we first subtract from both sides:
Then, we add to both sides:
Finally, we divide both sides by
Therefore,
Solve for in the figure above given that
Since the angles and are corresponding angles, they are congruent and therefore have the same measure:
Now, we have an equation that we can solve for
Solve for $y$ in the figure above given that $\overset{\longleftrightarrow}{AB} \parallel \overset{\longleftrightarrow}{CD}.$
a
|
$110^\circ$ |
b
|
$100^\circ$ |
c
|
$105^\circ$ |
d
|
$90^\circ$ |
e
|
$85^\circ$ |
Solve for $x$ in the figure above given that $\overset{\longleftrightarrow}{AB} \parallel \overset{\longleftrightarrow}{CD}.$
a
|
$8^\circ$ |
b
|
$15^\circ$ |
c
|
$7^\circ$ |
d
|
$24^\circ$ |
e
|
$18^\circ$ |
Solve for in the figure above given that
Since the angles and are corresponding angles, they are congruent and therefore have the same measure:
Now, we have an equation that we can solve for
Solve for $x$ in the figure above given that $\overset{\longleftrightarrow}{AB} \parallel \overset{\longleftrightarrow}{CD}.$
a
|
$13^\circ$ |
b
|
$16^\circ$ |
c
|
$23^\circ$ |
d
|
$9^\circ$ |
e
|
$6^\circ$ |
Solve for $x$ in the figure above given that $\overset{\longleftrightarrow}{AB} \parallel \overset{\longleftrightarrow}{CD}.$
a
|
$22^{\circ}$ |
b
|
$16^{\circ}$ |
c
|
$15^{\circ}$ |
d
|
$23^{\circ}$ |
e
|
$20^{\circ}$ |
Given that , and in the above diagram are parallel, find
Consider and in the diagram below.
Note that and the angle whose measure is are corresponding angles formed by the same transversal. Therefore,
Similarly, note that and the angle whose measure is are corresponding angles formed by the same transversal. Therefore,
Let's add these measures to our diagram:
The angles , and combine to give a straight angle. So, we get
Given that $r$, $s$ and $t$ in the above diagram are parallel, find $m\angle{w}.$
a
|
$60^\circ$ |
b
|
$56^\circ$ |
c
|
$59^\circ$ |
d
|
$50^\circ$ |
e
|
$69^\circ$ |
Given that $r$, $s$ and $t$ in the above diagram are parallel, find $m\angle{1}.$
a
|
$52^\circ$ |
b
|
$43^\circ$ |
c
|
$30^\circ$ |
d
|
$40^\circ$ |
e
|
$45^\circ$ |
Solve for in the figure above given that
Consider and in the diagram below.
Note that and the angle whose measure is are corresponding angles formed by the same transversal. Therefore,
Similarly, note that and the angle whose measure is are corresponding angles formed by the same transversal. Therefore,
Let's add these measures to our diagram.
The angles , and the third angle whose measure is , combine to give a straight angle. So, we get
Solve for $x$ in the figure above given that $s \parallel t.$
a
|
$4^{\circ}$ |
b
|
$11^{\circ}$ |
c
|
$7^{\circ}$ |
d
|
$8^{\circ}$ |
e
|
$5^{\circ}$ |
Solve for $x$ in the figure above given that $s \parallel t.$
a
|
$20^{\circ}$ |
b
|
$17^{\circ}$ |
c
|
$12^{\circ}$ |
d
|
$22^{\circ}$ |
e
|
$15^{\circ}$ |