1. Suppose S is between R and T
Suppose S is between R and T. Use the Segment Addition Postulate or sum of the parts = whole or the add two parts of a line together thing to solve for the variable.
RS = 12, ST = 2x, RT = 34 1.
RS = 16, ST = 2x, RT = 5x+10 2. 3.
RS = 4y-1, ST = 2y-1, RT = 5y 4.
RS = 2z+6, ST = 4z-3, RT = 5z+12

2. Find the value of the variable and PB, if P is between A and B.
AP=-2s, PB=s+8, AB=11 1.

3. Lesson 1-4
Learners will be able to measure and classify angles, congruent angles, and angle bisectors.

4. A ray is a part of a line. It has one endpoint and extends indefinitely in one direction.
Rays are named stating the endpoint first and then any other point on the ray.

5. If you choose a point on a line, you make exactly two rays called opposite rays.Z Y X Y Z
Name the 2 Rays…

6. An angle is the intersection of two noncollinear rays at a common endpoint.
The common endpoint is called the vertex, and the rays are the sides of the angle.

7. An angle can be named by a single letter… ex: B
Or by three letters: a point on one side, the vertex, and a point on the other side.… ex: ABC

8. Name all angles that have B as a vertex.
Answer: 5, 6, 7, and ABG
Example 4-1a

9. Answer: and or are the sides of 5.
Name the sides of 5.
Answer: and or are the sides of 5.
Example 4-1b

10. Write another name for 6.
Answer: EBD, FBD, DBF, and DBE are other names for 6.
Example 4-1c

11. a. Name all angles that have X as a vertex.
b. Name the sides of 3.
c. Write another name for 3.
Answer: 1, 2, 3, and RXB or RXN
Answer:
Answer: AXB, AXN, NXA, BXA
Example 4-1d

12. There is an interior and an exterior of an angleZ B C W
Where is point Z? W? C?

13. Angles are measured in degrees.
What are degrees?
Da sun
1 of a circle
360

14. Logically where is a 45 angle?
A right angle is an angle with a measurement of 90
Logically where is a 45 angle?

15. Obtuse: which have a measurement greater than 90
There are two other types of angles beside right angles….
90 < mABC < 180 A C B
Obtuse: which have a measurement greater than 90

16. Acute: which have a measurement lesser than 90
There are two other types of angles beside right angles…. A
mABC < 90 C B
Acute: which have a measurement lesser than 90

17. Measure TYV and classify it as right, acute, or obtuse.
TYV is marked with a right angle symbol, so measuring is not necessary.
Answer: is a right angle.
Example 4-2a

18. Measure WYT and classify it as right, acute, or obtuse.
Use a protractor to find that .
Answer: > is an obtuse angle.
Example 4-2b

19. Measure each angle named and classify it as right, acute, or obtuse.
a. CZD
b. CZE
c. DZX
Answer: 150, obtuse
Answer: 90, right
Answer: 30, acute
Example 4-2d

20. Just like with congruent sides we also have congruent anglesB

21. A ray or line that divides an angle into two congruent angles is called an angle bisector

22. A ray or line that divides an angle into two congruent angles is called an angle bisector

23. 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 4-3a

24. Definition of congruent angles
Given
Definition of congruent angles
Substitution
Add 10 to each side.
Subtract 2x from each side.
Example 4-3b

25. Use the value of x to find the measure of one angle.
Given
or 35
Simplify.
Since .
Answer: Both measure 35.
Example 4-3c

26. SIGNS A railroad crossing sign forms congruent angles
SIGNS A railroad crossing sign forms congruent angles. In the figure, WVX ZVY. If mWVX 7a and mZVY 10a – 20, find the actual measurements of WVX and ZVY.
Answer:
Example 4-3d

27. Homework: Lesson 1-4, p. 33 # 4-36 even 42, 50