Yesterday we learned the five major angle pairs that are created when two lines are cut by a transversal.[br][br]Below you will see that we have two lines and a transversal.
Click on point B and move it around. What do you notice?
Now you will see that[math]\angle ECD[/math] has been measured. Measure the angle that creates a set of [b]corresponding angles[/b]. To do this, click on the angle tool ([icon]https://www.geogebra.org/images/ggb/toolbar/mode_angle.png[/icon]) and click the three points that form the angle.
What do you notice? Is what you noticed still true if you move point B?
Now you will see that [math]\angle FCE[/math] has been measured. Measure the angle that creates a pair of [b]Alternate Exterior Angles[/b].
What do you notice about these angles? Is what you noticed still true if you move point B?
Now you will see that [math]\angle GAC[/math] has been measured. Measure the angle that creates a pair of [b]Alternate Interior Angles[/b].
What do you notice about these angles? Is what you noticed still true if you move point B?
Next, measure a set of [b]Consecutive (same-side) Exterior Angles[/b].
What do you notice about these angles? Is what you noticed still true if you move point B?
Lastly, measure a set of [b]Consecutive(same-side) Interior Angles[/b].
What do you notice about these angles? Is what you noticed still true if you move point B?
By completing this activity you should have noticed that two parallel lines are cut by a transversal create angle pairs with specific relationships. Some angle pairs were equal ([b]congruent[/b]) while others added up to equal 180 degrees ([b]supplementary[/b]). [br][br]Which angle pairs are [b]congruent[/b] when created by parallel lines and a transversal?
Which angle pairs are [b]supplementary[/b] when created by parallel lines and a transversal?
Now let's look at angle pairs that are created by only two lines instead of three.
What do we call this angle pair?
What do you notice about these angles? Is what you noticed still true if you move point B around?
What do we call this angle pair?
What do you notice about these angles? Is what you notice still true if you move point B?
What do you know about [math]\angle BCE[/math]? (select all that apply)
Can you find the measure of the other three angles without using the Geogebra tool? Explain how.
Now use the angle tool to check your answers. Were you correct?