1. LESSON 1–4
Angle Measure

2. Five-Minute Check (over Lesson 1–3) TEKS Then/Now New Vocabulary
Example 1: Real-World Example: Angles and Their Parts
Key Concept: Classify Angles
Example 2: Measure and Classify Angles
Example 3: Measure and Classify Angles
Lesson Menu

3. Use the number line to find the measure of AC.
5-Minute Check 1

4. Use the number line to find the measure of DE.
C. 7
D. 9
5-Minute Check 2

5. Use the number line to find the midpoint of EG.
A. D
B. E
C. F
D. H
5-Minute Check 3

6. Find the distance between P(–2, 5) and Q(4, –3).
5-Minute Check 4

7. Find the coordinates of R if M(–4, 5) is the midpoint of RS and S has coordinates (0, –10).
B. (–4, 15)
C. (–2, –5)
D. (2, 20)
5-Minute Check 5

8. A boat located at (4, 1) can dock at two locations
A boat located at (4, 1) can dock at two locations. Location A is at (–2, 9) and Location B is at (9, –11). Which location is closest? How many units away is the closest dock?
A. Location A, 10 units
B. Location A, 12.5 units
C. Location B, 10 units
D. Location B, 12.5 units
5-Minute Check 6

9. Mathematical Processes G.1(D), Also addresses G.1(E)
Targeted TEKS
G.5(B) Construct congruent segments, congruent angles, a
segment bisector, an angle bisector, perpendicular lines, the perpendicular bisector of a line segment, and a line parallel to a given line through a point not on a line using a compass and
a straightedge.
Mathematical Processes
G.1(D), Also addresses G.1(E)
TEKS

10. You measured line segments.
Measure and classify angles.
Identify and use congruent angles and the bisector of an angle.
Then/Now

11. ray degree right angle acute angle opposite rays angle obtuse angle
angle bisector
opposite rays
angle
side
vertex
interior
exterior
Vocabulary

12. A. Name all angles that have B as a vertex.
Angles and Their Parts
A. Name all angles that have B as a vertex.
Answer:
Example 1

13. Angles and Their Parts
B. Name the sides of 5.
Answer:
Example 1

14. Angles and Their Parts C.
Example 1

15. A. A. B. C. D.
Example 1a

16. B. A. B. C.
D. none of these
Example 1b

17. Which of the following is another name for 3?B. C. D.
Example 1c

18. Concept

19. A. Measure TYV and classify it as right, acute, or obtuse.
Measure and Classify Angles
A. Measure TYV and classify it as right, acute, or obtuse.
Answer: mTYV = 90, so TYV is a right angle.
Example 2

20. Answer: 180 > mWYT > 90, so WYT is an obtuse angle.
Measure and Classify Angles
Answer: 180 > mWYT > 90, so WYT is an obtuse angle.
Example 2

21. Measure and Classify Angles
Example 2

22. A. Measure CZD and classify it as right, acute, or obtuse.
A. 30°, acute
B. 30°, obtuse
C. 150°, acute
D. 150°, obtuse
Example 2a

23. B. Measure CZE and classify it as right, acute, or obtuse.
A. 60°, acute
B. 90°, acute
C. 90°, right
D. 90°, obtuse
Example 2b

24. C. Measure DZX and classify it as right, acute, or obtuse.
A. 30°, acute
B. 30°, obtuse
C. 150°, acute
D. 150°, obtuse
Example 2c

25. Measure and Classify Angles
INTERIOR DESIGN Wall stickers of standard shapes are often used to provide a stimulating environment for a young child’s room. A five-pointed star sticker is shown with vertices labeled. Find mGBH and mHCI if GBH  HCI, mGBH = 2x + 5, and mHCI = 3x – 10.
Example 3

26. mGBH = mHCI Definition of congruent angles
Measure and Classify Angles
Step 1 Solve for x.
GBH  HCI Given
mGBH = mHCI Definition of congruent angles
2x + 5 = 3x – 10 Substitution
2x + 15 = 3x Add 10 to each side.
15 = x Subtract 2x from each side.
Example 3

27. Step 2 Use the value of x to find the measure of either angle.
Measure and Classify Angles
Step 2 Use the value of x to find the measure of either angle. .
Answer: mGBH = 35, mHCI = 35
Example 3

28. Find mBHC and mDJE if BHC  DJE, mBHC = 4x + 5, and mDJE = 3x + 30.
A. mBHC = 105, mDJE = 105
B. mBHC = 35, mDJE = 35
C. mBHC = 35, mDJE = 105
D. mBHC = 105, mDJE = 35
Example 3

29. LESSON 1–4
Angle Measure