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. Let’s 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. factor must be a relation by multiplying. Now take a look at the 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. Both 2 and 3 are multiplied by 4. This means the scale factor is 4. 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 B C D 3
1/3 5 10

9. What is the scale factor?8 16 B A C D 3 2
1/2 8

10. What is the scale factor?4 12 A B C D 3
1/2
1/3 9

11. What is the scale factor?3 18 A B C D 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 B C D
9 in
16 in
16 ft
8 in