# Properties of Parallel Lines

- Author:
- L Sliver, GeoGebra Materials Team

When a transversal intersects parallel lines, what is the relationship between corresponding angles?

When a transversal intersects parallel lines, what is the relationship between alternate interior angles?

When a transversal intersects parallel lines, what is the relationship between same-side interior angles?

## This question has four parts (a-d)

a. Identify a pair of corresponding angles: ____________ & ____________.

b. Record the measure of each: ____________ & ____________.

## Move either the transversal and/or the parallels, by moving points A, B, or C.

c. Record the measures of the same two angles: ____________ & ____________.

## Form a conclusion from your observations:

d. If parallel lines are cut by a transversal, then corresponding angles are ___________________.

## This question has four parts (a-d)

a. Identify a pair of alternate interior angles: ____________ & ____________.

b. Record the measure of each: ____________ & ____________.

## Move either the transversal and/or the parallels, by moving points A, B, or C.

c. Record the measures of the same two angles: ____________ & ____________.

## Form a conclusion from your observations:

d. If parallel lines are cut by a transversal, then alternate interior angles are ___________________.

## This question has four parts (a-d)

a. Identify a pair of same-side interior angles: ____________ & ____________.

b. Record the measure of each: ____________ & ____________.

## Move either the transversal and/or the parallels, by moving points A, B, or C.

c. Record the measures of the same two angles: ____________ & ____________.

## Form a conclusion from your observations:

d. If parallel lines are cut by a transversal, then same-side interior angles are ___________________.