Transcript Similar Figures

Do Now 3/13/12
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Take out HW from last night.
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Copy HW in your planner.
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p. 307, #2-32 evens
p. 312, #1-16 all, 21
In your notebook, list as many words as
you can that can be associated with
“geometry.” For each word draw the
matching symbol or figure.
Homework
Text p. 307, #2-32 evens
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2) ordered pair
4) integer
6) 6%
8) 104%
10) 0.8
12) 1.31
14) 12
16) 81
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18) 563.2
20) 118
22) 32
24) 104
26) 56
28) (3,3)
30) (5,1)
32) (6,4)
Objective
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SWBAT identify and describe geometric
figures
Section 8.1 “Building Blocks of
Geometry”
Point
an exact location,
represented as a dot.
A
L
D
Z
K
Plane
a flat surface that extends on
forever in all directions.
How many planes on this figure?
Line segment
part of a line with 2 endpoints
and all the points in between.
D
EF
FE
E
C
CD DC
F
Line
a straight path extending
without end in opposite directions.
R
S
ST
T
RT
RS
Ray
Part of a line that begins
at a point and extends in one
direction without ending.
B
A
A
K
AB
J
K
JK
Identifying Points, Lines, and Planes
Identify the figures in the diagram.
G
I
H
F
A. four points
H, G, I, and F
B. two lines
IH, HF
C. a plane
plane IGF
Choose any two points on
a line to name the line.
Choose any three points,
not on the same line, in
any order.
Identifying Line Segments and Rays
Identify the figures in the diagram.
M
N
O
A. three rays
MN, NM, MO
Name the endpoint of
a ray first.
B. two line segments
Use the endpoints in
any order to name a
segment.
MN, MO
“Similar Figures”
Similar Figures
Two figures are SIMILAR FIGURES if they have
the same shape but not necessarily the same
size. The symbol ~ indicates two figures are
similar.
Properties of similar figures:
1). Corresponding angles are congruent
2). Corresponding sides are proportional (equal ratios)
Corresponding angles –
matched angles of two figures
ABC ~ DEF
A  D
C  F
When 2 angles
have the same
measure, they are
marked with the
same symbol.
A
D
F
 B  E
E
C
B
Corresponding sides –
matched sides of two figures
D
A
F
E
C
B
Congruent
Two line segments are
congruent when they are the
same length.
C
3
CD  EF
EF  3
D
E
F
You can use tick marks to
indicate congruent line segments.
Congruent Figures
Two figures are CONGRUENT FIGURES if they
have the same shape AND the same size.
Properties of congruent figures:
1). Corresponding angles are congruent
2). Corresponding sides are congruent
Identifying Congruent Line Segments
Identify the line segments that are congruent
in the figure.
AB  CD
One tick mark
AC  BD
Two tick marks
BF  DF  EC  AE Three tick
marks
Reading Math
The symbol  means “is congruent to.”
Identifying Congruent Line Segments
Identify the line segments that are congruent
in the figure.
A
B
C
D
E
AB  AC
One tick mark
BC  DE
Two tick marks
BD  CE
Three tick marks
Given
ABC  XYZ, find the indicated measure.
Z
A
X
15
45
20
Y
35°
C
B
YX 
CB 
45
15
mZ  90°
mY  35°
mA  55°
Puzzler…
Remove 4 of the segments to leave 5
equal squares.
Homework
Text p. 312, #1-16 all, 21