Plane Geometry Unit 1 – Chapter 1
Download
Report
Transcript Plane Geometry Unit 1 – Chapter 1
SECTION 1.2 NOTES
Postulate or Axiom – a rule that is accepted without proof.
Ruler Postulate
The points on any line can be matched to real numbers,
that real number is known as the coordinate of that point.
The distance between any two points A and B, is written
as AB and is the absolute value of the difference of the
Names
coordinates of A and B.
A
x1
Coordinates
DISTANCE
AB = |x1 – x2|
B
x2
SECTION 1.2 NOTES
Segment Addition Postulate:
Between - is only when three points are collinear
If B is between A and C, then AB + BC = AC
If AB + BC = AC, then B is between A and C.
AC
B
A
AB
C
BC
SECTION 1.2 NOTES
Congruency:
Congruent Segments – line segments that have the same
length.
Equal vs. Congruence
AB = CD
A
B
lengths are equal
C
D
Mathematical Notation: Congruent
AB ≅ CD
Segments are congruent
SECTION 1.2 NOTES
Using the ruler postulate...
W
-10
Y
X
-8
-6
-4
-2
0
2
4
Z
6
Find:
1) WX
2) XY
3) WY
4) ZW
8
10
SECTION 1.2 NOTES
Points G, H, I, J and K are collinear. GK = 24, HJ = 10, and GH =
HI = IJ. Find each length
24
G
H
I
10
K
J
1) HI
2) IJ
3) GH
4) JK
5) IG
6) GK
SECTION 1.2 NOTES
Find RS, QS, and TV using the following information:
S is between T and V. R is between S and T. T is between R
and Q. QV = 23, QT = 8, and TR = RS = SV
V
S
R
Q
T
23
?
8
SECTION 1.2 NOTES
Point J is between M and N. Find the length of JM and JN
given the following information. JM = 7x + 2, MN = 64,
and JN = 2x – 1.
M
N
J
64
7x + 2
2x – 1
So (7x + 2) + (2x – 1) = 64
9x + 1 = 64
9x = 63
x=7
JM: 7(7) + 2 = 51
JN: 2(7) – 1 = 13
SECTION 1.2 NOTES
Point M is between V and W. Find the length of VM and MW,
given the following information. VM = 4x – 1, VW = 30,
and MW = 3x + 3.
V
W
M
30
4x – 1
3x + 3
So (3x + 3) + (4x – 1) = 30
7x + 2 = 30
7x = 28
x=4
MW: 3(4) + 3 = 15
MV: 4(4) – 1 = 15
CONCEPT CHECK
P. 10-11
#3 – 6
“Guided Practice”
HOMEWORK
P. 12-13
#6 - 30
(Omit #12)