scale factor

1
scale factor
2

• Scale factor is the ratio of change between two
  sides.
• The number you multiply by to relate the first
  shape to the second is the scale factor.

3
If a shape becomes twice as big, the scale
factor would be two. If a shape shrinks to half
its size, the scale factor is ½. Lets take a
look.
4
Now Look at the BLUE translation and write down
the base and height
Take a look at the RED shape, write down the
base and height
5
How many times bigger is the blue shape?
2 is your scale factor because 5 x 2 10 and 4
x 2 8
What did you get?
5
10
4
8
6
6
9
2
3
For 6 to become 2, you must multiply by 1/3 and
for 9 to become 3 you must also multiply by
1/3. So your scale factor is.1/3
Both 6 and 9 reduce in size by dividing 3 BUT
scale factor must be a relation by multiplying.
Now take a look at the transformation, what has
been the amount of reduction?
7
2
3
8
12
Both 2 and 3 are multiplied by 4. This means
the scale factor is 4.
Now take a look at the transformation, what has
been the amount of enlargement?
8
What is the scale factor?
5
15
7
21
A
D
B
C
3
1/3
5
10
9
What is the scale factor?
8
16
B
A
D
C
3
2
1/2
8
10
What is the scale factor?
4
12
A
D
C
B
3
1/2
1/3
9
11
What is the scale factor?
3
18
A
D
C
B
9
4
1/6
6
12
A Mustang GT is 16 feet long. A model of it was
built with a scale of 1 in 2 ft. How long is
the model.
A
C
B
D
9 in
16 in
16 ft
8 in