1. 1.4 Angle Measure Then: You measured line segments.
Now: 1. Measure and classify angles.
2. Identify and use congruent angles and
the bisector of an angle.
When is a miter
joint used?

2. Vocabulary
11. Ray- part of a line with one endpoint that continues indefinitely in one direction. Notation- start with endpoint then another point the ray goes through.

3. Vocabulary
12. Opposite rays- share a common endpoint and are collinear. 𝑩𝑨 and 𝑩𝑪 are opposite rays.

4. Vocabulary
13. Angle- intersection of two noncollienar rays , called the sides, at a common endpoint, called the vertex. Naming angles- R, MRS, SRM or 2 2

5. Example 1: Angles and Their Parts
Use the figure to answer the questions.
a. Name all the angles that have
B as a vertex.
b. Name the sides of 5.
c. Write another name for6.

6. Example 1
d. What is another name for FED? e. Name a point in the exterior of ABD.

7. Vocabulary Right angle- an angle with a degree measure of 90.
Acute angle- an angle with a degree measure less than 90.
Obtuse angle- an angle with a degree measure greater than 90and less than 180.

8. Example 2: Measure and Classify Angles
Classify each angle as right, acute, or obtuse. Then use a protractor to measure the angle to the nearest degree.
a. ABD
b. DBC
c. EBC

9. Vocabulary 17. Congruent angles:
Angles that have the same measure are congruent.
A  B
18. Angle bisectors:
A ray that divides an angle into 2 congruent angles.
LKM  JKM

10. Example 3: Use Algebra to Find Measures
a. In the figure 𝑸𝑷 and 𝑸𝑹 are opposite rays and 𝑸𝑺 bisects PQT. If m PQS = 3x + 13 and m SQT = 6x – 2, find m PQT. Work:

11. Example 3: Use Algebra to Find Measures
b. In the figure 𝑩𝑨 and 𝑩𝑪 are opposite rays. 𝑩𝑭 bisects CBE. If m EBF = 6x + 4 and m CBF = 7x – 2, find m EBF. Work:

12. p. 41-44 # 12-34 evens, 38-44 evens, 45 &46 graph, 52, 58, 64,
1.4 Assignment
p # evens, evens, 45 &46 graph, 52, 58, 64,