Post on 01-Jan-2016
Process
What is the ratio of the corresponding sides of the blue triangle to the red triangle?
3 5
4
610
8
The ratio of corresponding sides of a figure is called the scale factor.
In this problem the scale factor is 2. This is an enlargement because the scale factor is greater than 1.
From
To
__
Process
What is the ratio of the corresponding sides of the red triangle to the blue triangle?
35
4
6
10
8
The ratio of corresponding sides of a figure is called the scale factor.
In this problem the scale factor is 1/2. This is a reduction because the scale factor is less than 1..
From
To
__
To
(x,y) (x’,y’)
(0,0) (3,0)
(0,3) (3,3)
(0,0)
(6,0)
(6,6)(0,6)
The above rectangle was dilated by a What are the coordinates of vertices of the new rectangle? (0,0), (6,0), (0,6) and (6,6)
scale factor of 2.
(2x,2y)(2*0, 2*0)
(2*3, 2*0)
(2*3, 2*3)(2*0, 2*3)
Triangle ABC was dilated to produce triangle A’B’C’. What scale factor was used to produce this dilation?
From Tox x’
RateScale Factor
( 2,0) (8,0)
2 8
82 = 4
In the previous problem, We used the x –value of the ordered pairs on the x-axis. Predict what would happen if we used the y –value of the ordered pairs on the y-axis.
From Toy y’
RateScale Factor
2 8
(0,2)
(0,8)
The scale factor is the same.
Regular pentagon ABCDE is similar to regularpentagon MNOPQ. The scale factor is 2.5. Whatis the length of the sides of pentagon MNOPQ.
Missing Sides and Angles
2
A
B
CD
E
?
M
N
OP
Q
Scaling Up or Down
Determine the scale factor used to go from figure A to figure B.
AB
A
B
A B3. Scale factor ________
2. Scale factor ________
1. Scale factor ________
1.5
62
3 1
4
Scaling Up or DownGuided Practice
Determine the scale factor used to go from figure A to figure B.
AB
A
B
A B3. Scale factor ________
2. Scale factor ________
1. Scale factor ________
1.5
62
3 1
6