1. WARM UP 1.5
On desk!

2. REVIEW Daily Quiz 1.4
Use the diagram at the right. 1.
Name the intersection of BE and CD.
point D
ANSWER 2.
Name the intersection of BE and plane A.
point B
ANSWER 3.
Name the intersection of DB and plane F.
Point E
ANSWER

3. 4.
Name the intersection of planes A and F.
Use the diagram at the right.
The planes do not appear to intersect.
ANSWER 5.
Sketch two lines that intersect a plane at the same point.
ANSWER
Sample answer:

4. 1.5
ESSENTIAL OBJECTIVE:
How do we apply the ruler postulate and the segment addition postulate?

5. VOCABULARY
The real number that corresponds to a point is the coordinate of a point.
The distance between points A and B, written AB, is the absolute value of the difference of the coordinates of A and B.

6. VOCABULARY
The real number that corresponds to a point is the coordinate of a point.
The distance between points A and B, written AB, is the absolute value of the difference of the coordinates of A and B.
AB is also called the length of AB .

7. VOCABULARY
Segments that have the same length are called congruent segments.

8. Segment Addition Postulate
If B is between A and C, then AC= AB + BC.
If AC = AB + BC, then B is between A and C.

9. Segment Addition Postulate
If B is between A and C, then AC= AB + BC.
If AC = AB + BC, then B is between A and C.

10. Segment Addition Postulate
If B is between A and C, then AC= AB + BC.
If AC = AB + BC, then B is between A and C.

11. Segment Addition Postulate
If B is between A and C, then AC= AB + BC.
If AC = AB + BC, then B is between A and C.

12. the distance from Athens to Albany.
Example 2
Find a Distance by Adding
Use the map to find
the distance from Athens
to Albany.
SOLUTION
Because the three cities lie
on a line, you can use the
Segment Addition Postulate.
AB = AM + MB =
= 170
ANSWER
The distance from Athens to Albany is 170 miles. 12

13. Use the diagram to find EF.
Example 3
Find a Distance by Subtracting
Use the diagram to find EF.
SOLUTION
DF = DE + EF
Segment Addition Postulate
16 = 10 + EF
Substitute 16 for DF and 10 for DE.
16 – 10 = 10 + EF – 10
Subtract 10 from each side.
6 = EF
Simplify. 13

14. Checkpoint Find the length. 3. Find AC. 4. Find ST.
Use the Segment Addition Postulate
Find the length. 3.
Find AC. 4.
Find ST.

15. More……… Find the length. 3. Find AC. ANSWER 20 4. Find ST. ANSWER 8
Use the Segment Addition Postulate
Find the length. 3.
Find AC.
ANSWER 20 4.
Find ST.
ANSWER 8

16. Are the segments shown in the coordinate plane congruent?
Example 4
COORDINATE PLANE: Absolute Value Sign
Are the segments shown in the coordinate plane congruent?
SOLUTION
For a horizontal segment,
DE = 1 – (–3) = = 4
For a vertical segment,
FG = –3 –1 = –4 = 4
ANSWER
DE and FG have the same length. So, DE  FG. 16

17. GIZMOS:
Distance in the X-Y Plane

18. GRAPHING PAPER! Exit Ticket
Use Graphing Paper and plot the points.
Plot the points in a coordinate plane. Then decide whether AB and CD are congruent. 1.
A(–2, 3), B(3, 3), C(–3, 4), D(–3, –1) 2.
A(0, 5), B(0, –1), C(5, 0), D(–1, 0)
GRAPHING PAPER!

19. Exit Ticket
Use Graphing Boards and plot the points.
Plot the points in a coordinate plane. Then decide whether AB and CD are congruent. 1.
A(–2, 3), B(3, 3), C(–3, 4), D(–3, –1)
ANSWER
yes; 2.
A(0, 5), B(0, –1), C(5, 0), D(–1, 0)
ANSWER
yes;

20. Daily Quiz
Hw Worksheet 1.5 B