1. Splash Screen

2. Five-Minute Check (over Lesson 1–2) Then/Now New Vocabulary
Key Concept: Distance Formula (on Number Line)
Example 1: Find Distance on a Number Line
Key Concept: Distance Formula (in Coordinate Plane)
Example 2: Find Distance on Coordinate Plane
Key Concept: Midpoint Formula (on Number Line)
Example 3: Real-World Example: Find Midpoint on Number Line
Key Concept: Midpoint Formula (in Coordinate Plane)
Example 4: Find Midpoint in Coordinate Plane
Example 5: Find the Coordinates of an Endpoint
Example 6: Use Algebra to Find Measures
Lesson Menu

3. What is the value of x and AB if B is between A and C, AB = 3x + 2, BC = 7, and AB = 8x – 1?
A. x = 2, AB = 8
B. x = 1, AB = 5 C.
D. x = –2, AB = –4 A B C D
5-Minute Check 1

4. If M is between L and N, LN = 3x – 1, LM = 4, and MN = x – 1, what is the value of x and MN?
A. x = 1, MN = 0
B. x = 2, MN = 1
C. x = 3, MN = 2
D. x = 4, MN = 3 A B C D
5-Minute Check 2

5. Find RT. A. B. C. D. .
in. A B C D
5-Minute Check 3

6. A B C D What segment is congruent to MN? A. MQ B. QN C. NQ
D. no congruent segments A B C D
5-Minute Check 4

7. A B C D What segment is congruent to NQ? A. MN B. NM C. QM
D. no congruent segments A B C D
5-Minute Check 5

8. A. 5
B. 6
C. 14
D. 18 A B C D
5-Minute Check 6

9. You graphed points on the coordinate plane. (Lesson 0–2)
Find the distance between two points.
Find the midpoint of a segment.
Then/Now

10. distance
midpoint
segment bisector
Vocabulary

11. Concept

12. Use the number line to find QR.
Find Distance on a Number Line
Use the number line to find QR.
The coordinates of Q and R are –6 and –3.
QR = | –6 – (–3) | Distance Formula
= | –3 | or 3 Simplify.
Answer: 3
Example 1

13. A B C D Use the number line to find AX. A. 2 B. 8 C. –2 D. –8
Example 1

14. Concept

15. Find the distance between E(–4, 1) and F(3, –1).
Find Distance on a Coordinate Plane
Find the distance between E(–4, 1) and F(3, –1).
(x1, y1) = (–4, 1) and (x2, y2) = (3, –1)
Example 2

16. Find Distance on a Coordinate Plane
Check Graph the ordered pairs and check by using the Pythagorean Theorem.
Example 2

17. Find Distance on a Coordinate Plane.
Example 2

18. A B C D Find the distance between A(–3, 4) and M(1, 2). A. 4 B. C. D.
Example 2

19. Concept

20. Find Midpoint on a Number Line
DECORATING Marco places a couch so that its end is perpendicular and 2.5 feet away from the wall. The couch is 90” wide. How far is the midpoint of the couch back from the wall in feet?
First we must convert 90 inches to 7.5 feet. The coordinates of the endpoints of the couch are 2.5 and 10. Let M be the midpoint of the couch.
Midpoint Formula
x1 = 2.5, x2 = 10
Example 3

21. Answer: The midpoint of the couch back is 6.25 feet from the wall.
Find Midpoint on a Number Line
Simplify.
Answer: The midpoint of the couch back is 6.25 feet from the wall.
Example 3

22. DRAG RACING The length of a drag racing strip is. mile long
DRAG RACING The length of a drag racing strip is mile long. How many feet from the finish line is the midpoint of the racing strip?
A. 330 ft
B. 660 ft
C. 990 ft
D ft A B C D
Example 3

23. Concept

24. Find Midpoint in Coordinate Plane
Answer: (–3, 3)
Example 4

25. A. (–10, –6)
B. (–5, –3)
C. (6, 12)
D. (–6, –12) A B C D
Example 4

26. Let D be (x1, y1) and F be (x2, y2) in the Midpoint Formula.
Find the Coordinates of an Endpoint
Let D be (x1, y1) and F be (x2, y2) in the Midpoint Formula.
(x2, y2) =
Write two equations to find the coordinates of D.
Example 5

27. Answer: The coordinates of D are (–7, 11).
Find the Coordinates of an Endpoint
Midpoint Formula
Midpoint Formula
Answer: The coordinates of D are (–7, 11).
Example 5

28. Find the coordinates of R if N (8, –3) is the midpoint of RS and S has coordinates (–1, 5).
B. (–10, 13)
C. (15, –1)
D. (17, –11) A B C D
Example 5

29. Use Algebra to Find Measures
Understand You know that Q is the midpoint of PR, and the figure gives algebraic measures for QR and PR. You are asked to find the measure of PR.
Example 6

30. Plan Because Q is the midpoint, you know that
Use Algebra to Find Measures
Plan Because Q is the midpoint, you know
that
Use this equation and the algebraic measures to find a value for x.
Solve
Subtract 1 from each side.
Example 6

31. Use Algebra to Find Measures
Original measure
Example 6

32. QR = 6 – 3x Original Measure
Use Algebra to Find Measures
Check
QR = 6 – 3x Original Measure
Example 6

33. Use Algebra to Find Measures
Multiply.
Simplify.
Example 6

34. A. 1
B. 3
C. 5
D. 10 A B C D
Example 6

35. End of the Lesson