1. Investigating Angle Relationships
What’s the Angle?
Investigating Angle Relationships

2. What’s the Angle? Fold a piece of notebook paper vertically in half.
Once more, fold the paper vertically in half.

3. What’s the Angle?
Use a ruler and a marker and trace the vertical line segment in the middle of the page.
This line segment is called a transversal.
A transversal is a line that crosses at least two other lines.

4. What’s the Angle?
In the upper left quadrant, mark a point on the left vertical fold and label it Point A.
In the upper right quadrant, mark a point on the right vertical fold that is 4 lines lower than Point A. Label it Point B.
Draw a line segment between points A and B.

5. What’s the Angle?
In the lower left quadrant, mark a point on the left vertical fold and label it Point C.
In the lower right quadrant, mark a point on the right vertical fold that is 4 lines lower than Point C. Label it Point D.
Draw a line segment between points C and D.

6. What’s the Angle?
On the left side of the transversal, label the angles formed as 1, 2, 3, and 4.
On the right side of the transversal, label the angles formed as 5, 6, 7, and 8.

7. What’s the Angle? What’s the Angle? Handout:
Lightly shade Angles 1, 5, 4, and 8 in blue. These are called exterior angles. Why?
Lightly shade Angles 2, 3, 6, and 7 in yellow. These are called interior angles. Why?

8. What’s the Angle? What’s the Angle? Handout:
Using a piece of patty paper, trace Angle 1 and determine which of the other angles are congruent to it. (Congruent means equal in measure.)
Use the patty paper to find other pairs of congruent angles. On your handout, list all of the pairs of congruent angles.

9. What’s the Angle? What’s the Angle? Handout:
If the sum of the degrees of two angles is 180, then the angles are called supplementary (also known as a linear pair). Using the patty paper, on your handout, list all of the pairs of angles that are supplementary.

10. What’s the Angle? What’s the Angle? Handout:
Angles that are opposite each other when two lines cross are called vertical angles. Vertical angles are congruent.
On your handout, list all the pairs of vertical angles.

11. What’s the Angle? What’s the Angle? Handout:
The angles in matching corners are called corresponding angles.
On your handout, list all the pairs of corresponding angles.

12. What’s the Angle? What’s the Angle? Handout:
Two angles are adjacent if they have a common side and a common vertex (corner point).
On your handout, list all the pairs of adjacent angles.

13. What’s the Angle?

14. What’s the Angle?
Find the measures of the numbered angles in the diagram.