RS = 12, ST = 2x, RT = 34

1. 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. A P 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. X Y X Y 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. X Y 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 A B C Or by three letters: a point on one side, the vertex, and a point on the other side.… ex: ABC

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

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

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

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

12. There is an interior and an exterior of an angle A Z 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. A right angle is an angle with a measurement of 90 Logically where is a 45 angle?

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

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

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

20. Just like with congruent sides we also have congruent angles A C B

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

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

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

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

26. SIGNS A railroad crossing sign forms congruent angles. In the figure, WVX ZVY. If mWVX 7a + 13and mZVY 10a – 20, find the actual measurements of WVXandZVY. Answer: Example 4-3d

27. Homework:Lesson 1-4, p. 33# 4-36 even42, 50