1. (-) + (-) = ? (+) x (+)= ? (-)+(+)= ? 12.07.2017 Ticket in the Door
Agenda
Ticket in the Door
Ticket in the Door
Review of Ticket in the Door
Current lesson:
Wrap-up
(-) + (-) = ?
(+) x (+)= ?
(-)+(+)= ?

2. scale factor

3. 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.

4. Understanding Scales
All scale drawings must have a scale written on them. Scales are usually expressed as ratios.
Normally for maps and buildings the ratio:
Drawing length: Actual length
For maps the ratio is normally in the ratio:
Map distance: Actual Distance
Example: 1cm : 100cm
The ratio 1cm:100cm means that for every 1cm on the scale drawing the length will be 100cm in real life
Example: 1:10000
The ratio 1:10000 means that the real distance is times the length of one unit on the map or drawing.

5. If you have ever seen Jurassic
Park, you saw how big the
dinosaurs were compared to the
people. Pretend that they made
a large Human to watch over the
animals. What would be the scale
factor if a 64 inch person was
made to be 160 feet?

6. The scale factor tells you how many times bigger than
“normal” that person really is.
You must make all units of
measure the same….
64 inches
64 inches
64 inches = =
160 feet
1920 inches
160 x 12

7. Now take the:
64 inches
And simplify
1920 inches
1/30 inches
This means that the person
was created 30 times his
normal size.

8. 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.

9. Take a look at the RED shape,
Now Look at the BLUE

10. How many times bigger is the blue shape?10
2 is your scale factor
because 5 x 2 = 10
and 4 x 2 = 8 5 4
What did you get? 8

11. transformation, what has been the amount of reduction?
Both 6 and 9 reduce in size
by dividing 3 BUT scale
factor must be a relation by
multiplying. 6
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 9 2 3
Now take a look at the
transformation, what has been
the amount of reduction?

12. 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?

13. What is the scale factor?5 15 7 21 A B C D 3
1/3 5 10

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

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

16. What is the scale factor?3 18 A B C D 9 4
1/6 6

17. 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