~ 7.3 ~
Nonadjacent Angles
Learning Targets
I can determine if angles that are not adjacent are complementary or supplementary.
I can explain what vertical angles are in my own words.
Notes
When two lines cross, they form two pairs of vertical angles. Vertical angles are across the intersection point from each other.
Vertical angles always have equal measure. We can see this because they are always supplementary with the same angle. For example:
This is always true!
a +b = 180 so a = 180 - b
c + b = 180 so c = 180 - b
That means a = c.
Vocabulary
vertical angles
Vertical angles are opposite angles that share the same vertex. They are formed by a pair of intersecting lines. Their angle measures are equal.
For example, angles AEC and DEB are vertical angles. If angle AEC measure 120°, then angle DEB must also measure 120°.
Angles AED and BEC are another pair of vertical angles.
Activities
3.2 Polygon Angles
Last lesson, we learned the meaning of complementary and supplementary when describing angles.
Use any useful tools in the geometry toolkit to identify any pairs of angles in these figures that are complementary or supplementary.
3.3 Vertical Angles
Use a straightedge to draw two intersecting lines. Use a protractor to measure all four angles whose vertex is located at the intersection.
Make a conjecture about the relationships between angle measures at an intersection.
intersecting
two lines that cross each other
conjecture
a statement we think is true, but aren’t certain about
Add to Your Notes
Do supplementary or complementary angles need to be next to one another?
Nope!
What are vertical angles?
A pair of angles across from one another where two lines cross.
What is true about the measures of vertical angles?
The measures of vertical angles are always the same!
Assignment
Check Google Classroom!