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1.2 – Segments and Congruence
Distance
Positive length between two points
Segments with the same length
AB  CD
Congruent
Segments
m AB  mCD
AB  CD
A
B
C
D
Postulate
Rules of geometry that are not
proved
The distance between 2 points is
the absolute value of the
difference between them.
Ruler
Postulate
1
2
3
7 – 2 = 5u
4
5
6
7
8
2 – 7 = 5u
Segment
Addition
Postulate
A
Adding two pieces of a
segment total the whole
B
AB + BC = AC
C
1. Measure the length of the segment to the nearest
tenth of a centimeter.
3.5
AB = ________cm
1. Measure the length of the segment to the nearest
tenth of a centimeter.
1.6
CD = ________cm
1. Measure the length of the segment to the nearest
tenth of a centimeter.
2.7
EF = ________cm
2. Find the indicated length.
GJ = _______
16u
16
2. Find the indicated length.
ST = _______
19u
37 – 18 = 19
2. Find the indicated length.
14u
YZ = _______
2x + 3 + 3x – 1 = 27
5x + 2 = 27
-2 -2
5x = 25
x=5
YZ = 3(5) – 1
YZ = 15 – 1
YZ = 14
3. Name the congruent segments using proper notation.
AB  CD
AD  CB
4. Use the number line to find the indicated measure.
5u
JK = _____
4u
KL = _____
9u
JL = _____
10u
MK = _____
5. Plot the given points in a coordinate plane. Then determine
whether the line segments named are congruent.
A(2, 2), B(2, –1), C(0, –2), D(3, –2)
AB and CD
AB = 3u
CD = 3u
A
AB  CD
B
C
D
5. Plot the given points in a coordinate plane. Then determine
whether the line segments named are congruent.
E(–3, 2), F(1, 2), G(2, 3), H(2, –2)
EF and GH
EF = 4u
G
E
F
GH = 5u
Not congruent
H
6. In the diagram, points P, Q, R, and S are collinear,
PS = 46, PR = 18, and PQ = QR. Find the indicated
length.
PQ = 9u
QR = 9u
QS = 37u
RS = 28u
18
46
9
9
28
7. Point J is between H and K.. Use the given information to draw a
diagram and write an equation in terms of x. Solve the equation. Then
find HJ and JK.
2x – 5
6x
HJ = 2x – 5
JK = 6x
HK = 27
J
H
27
HJ + JK = HK
2x – 5 + 6x = 27
8x – 5 = 27
+5 +5
8x = 32
8
8
x=4
HJ = 2x – 5
HJ = 2(4) – 5
HJ = 8 – 5
HJ = 3u
JK = 6x
JK = 6(4)
JK = 24u
K
7. Point J is between H and K.. Use the given information to draw a
diagram and write an equation in terms of x. Solve the equation. Then
find HJ and JK.
4x + 7
5x –
J
H
HJ = 4x + 7
JK = 5x – 8
HK = 53
53
HJ + JK = HK
4x + 7 + 5x – 8 = 53
9x – 1 = 53
+1 +1
9x = 54
9
9
x=6
HJ = 4x + 7
HJ = 4(6) + 7
HJ = 24 + 7
HJ = 31u
JK = 5x – 8
JK = 5(6) – 8
JK = 30 – 8
JK = 22u
8
K
HW Problem
1.2
12-14
1-19 odd, 21-29, 41
# 27
1.6x = x + 6
EG = 1.6(10)
0.6x = 6
x = 10
EG = 16
D
Compass, ruler, and protractor, and calculator due
Book Cover and Syllabus Due Monday!!!!!!