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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

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

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

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

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

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

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

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

distance midpoint segment bisector Vocabulary

Concept

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

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

Concept

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

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

Find Distance on a Coordinate Plane . Example 2

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

Concept

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

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

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. 1320 ft A B C D Example 3

Concept

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

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

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

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

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

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

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

Use Algebra to Find Measures Original measure Example 6

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

Use Algebra to Find Measures Multiply. Simplify. Example 6

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

End of the Lesson