1-3 Study Guide and Intervention

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NAME

DATE

1-3

PERIOD

Study Guide and Intervention Locating Points and Midpoints

Midpoint of a Segment If the coordinates of the endpoints of a segment are x1 and x2,

Midpoint on a Number Line

x +x

1 2 . then the coordinate of the midpoint of the segment is −

2

If a segment has endpoints with coordinates (x1, y1) and (x2, y2),

Midpoint on a Coordinate Plane

then the coordinates of the midpoint of the segment are

+x , ( x− 2 1

2

y +y

)

1 2 − .

2

−− Find the coordinate of the midpoint of PQ.

Example 1 P

Q

-3 -2 -1

0

1

2

The coordinates of P and Q are -3 and 1. −−− Geo-SG01-03-05-846589 -3 + 1 -2 If M is the midpoint of PQ, then the coordinate of M is − = − or -1. 2

−−− Find the coordinates of M, the midpoint of PQ, for P(-2, 4) and

Example 2 Q(4, 1).

+x y +y -2 + 4 4 + 1 , − ) = ( − , − ) or (1, 2.5) ( x− 2 2 2 2 1

2

1

2

Exercises Use the number line to find the coordinate of the midpoint of each segment. −−− 1. CE

−−− 2. DG

−− 3. AF

−−− 4. EG

−− 5. AB

−−− 6. BG

−−− 7. BD

−−− 8. DE

A –10 –8

B –6

C –4

–2

D

EF

0

2

G 4

6

8

Geo-SG01-03-06-846589

Find the coordinates of the midpoint of a segment with the given endpoints. 9. A(0, 0), B(12, 8)

10. R(-12, 8), S(6, 12)

11. M(11, -2), N(-9, 13)

12. E(-2, 6), F(-9, 3)

13. S(10, -22), T(9, 10)

14. K(-11, 2), L(-19, 6)

Chapter 1

18

Glencoe Geometry

Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.

M=

2

NAME

DATE

1-3

PERIOD

Study Guide and Intervention

(continued)

Locating Points and Midpoints Locate Points The midpoint of a segment is half the distance from one endpoint to the other. Points located at other fractional distances from one endpoint can be found using a similar method. m If the coordinates of the endpoints of a segment are x1 and x2 and the point is − n of the

Locating Points on a Number Line

distance from x1 to x2, then the coordinate of the point is x1

m If a segment has endpoints A(x1, y1) and B(x2, y2) and the point is − n of the distance from

Locating Points on a Coordinate Plane

Example 1

mx - x 

2 1 + − . n

(

mx2 - x1

my2 - y1

)

point A to point B, then the coordinates of the point are x1 + − , y1 + − . n n

1 Find the coordinates of a point − of the distance from A to B. 3

A

B

-6 -5 -4 -3 -2 -1 0

1

2

3

4

1 The coordinates of A and B are -5 and 2. If P is the point − of the distance from A to B, 3 2-(-5) 7 -8 then the coordinate of P is -5 + − = -5 + − = − ≈ -2.7. 3 3 3

Example 2 to B(4, 3).

(

1 Find the coordinates of P, a point − of the distance from A(-2, -4) 4

mx 2 - x 1

my 2 - y 1

P = x1 + − , y1 + − n n

(

)

(

) = (-2 +

4 - (-2) 4

3 - (-4) 4

− , -4 + −

)

Lesson 1-3

Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.

P19-001A-890857

)

6 7 1 1 = -2 + − , -4 + − or about - − , -2 − . 4

4

2

4

Exercises Use the number line to find the coordinate of the point the given fractional distance from A to B. 1 1. − 5 3 4. − 4

A –10

B –8

1 2. −

–6

–4

–2

0

2

4

6

8

10

2

3. − P19-002A-890857 3

3 1 5. − 4

2 6. − 5

−−− Find P on NM that is the given fractional distance from N to M. 1 ; N(-3, -2), M(1, 1) 7. − 5

2 9. − ; N(-7, 3), M(5, 2) 3

1 11. − ; N(-2, 5), M(0, -4) 4

Chapter 1

019_GEOCRMC01_715477.indd 19

1 8. − ; N(-2, -4), M(4, 4) 3

3 10. − ; N(-3, 1), M(2, 6) 4

2 12. − ; N(-2, -1), M(8, 3) 5

19

Glencoe Geometry

2nd Pass

8/7/14 5:40 PM