1. < is the less than symbol ∠ is the angle symbol
Section 1.6a
Exploring Angles
< is the less than symbol
∠ is the angle symbol

2. Warm Up 1. Draw AB and AC, where A, B, and C are noncollinear.
2. Draw opposite rays DE and DF.
Solve each equation.
3. 2x x – 4 + 3x – 5 = 180
4. 5x + 2 = 8x – 10

3. A ray is part of a line that extends indefinitely in one direction.
It has exactly one endpoint and that point is named first when naming the ray.
Ray AB or

4. Two rays create an angle.
The rays become the sides of the angle.
If two rays form a line, they are called opposite rays.
A. What are the opposite rays?
B. What kind of angle do they form?
C. How many degrees is this angle?

5. What are the sides of this angle? What is the vertex?
Other angles are formed by two non-collinear rays with a common endpoint called a vertex.
What are the sides of this angle?
What is the vertex?
How do you name this angle?
When naming an angle, use 3 letters in which the vertex MUST be the middle letter or you can name it by the number inside the angle.

6. You can also name an angle by its vertex ONLY if the vertex represents one single angle.
How many angles do you see?
What are they?

7. Write the different ways you can name the angles in the diagram.

8. Classifying angles: Greater than 180 ̊ but less than 360

9. An angle separates a plane into 3 parts, the interior of the angle, the exterior and the angle itself.
Angles are measured in units called ___________.
What tool is used to measure a segment?
What tool is used to measure an angle?

10. What other names can be used to identify ∠BCD?
Name the vertex of ∠ 1.
What are the sides of ∠ 2?

11. Give other names for: ∠ RSQ ∠ QTR ∠ SUR ∠ 7 ∠ 5 ∠ 6 ∠4 + ∠5 = ∠ ?
∠6 + ∠7 = ∠ ?
∠2 + ∠3 = ∠ ? U

12. Name 3 angles with vertex P.
What 2 angles add up to 180 degrees?
If ∠3 = 80 ̊ and ∠LPN = 100 ̊, Then m∠2 =

14. Find the measure of each angle
Find the measure of each angle. Then classify each as acute, right, or obtuse.
A. WXV
B. ZXW

15. Use the diagram to find the measure of each angle
Use the diagram to find the measure of each angle. Then classify each as acute, right, or obtuse.
a. BOA
b. DOB
c. EOC