# 1TH/Vwo §5.3 Scale

§5.3 Scale
LEARNING GOAL:
how to calculate scale using a ratio table
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Slide 1: Slide
WiskundeMiddelbare schoolhavo, vwoLeerjaar 1

This lesson contains 27 slides, with interactive quizzes and text slides.

Lesson duration is: 50 min

## Items in this lesson

§5.3 Scale
LEARNING GOAL:
how to calculate scale using a ratio table

#### Slide 2 -Slide

§5.3 Scale
HOW ?
BY MAKING RATIO TABLES FOR EVERY EXERCISE !!
JUST LIKE IN §5.1 and. §5.2
On the TEST about Ch5 this will be asked from all the time.

#### Slide 3 -Slide

§5.3 Scale
Celebrating your birthday, inviting 300 people,
is something done ON A LARGE SCALE.

#### Slide 4 -Slide

Vital question for 'scale':
'What does 1 cm in the drawing represent in reality?!'
This drawing could be a map of a town, a country or a
continent,
but also the drawing of a person, an animal, or whatever.
Let's look at a few examples!

#### Slide 7 -Slide

Vital question for 'scale':
What does 1 cm in the drawing represent in reality?!
This drawing could be a map of a town,
but also the drawing of an animal, or whatever.
Let's look at an example!

#### Slide 8 -Slide

Example of 'scale':

#### Slide 10 -Slide

What is the right scale for the drawing of the weasel?
A
1 : 7.5
B
15 : 1
C
1 : 15
D
30 : 2

#### Slide 14 -Slide

Scale  1 : 15  meaning   1 cm on the drawing
equals 15 cm in reality.

#### Slide 16 -Slide

Homework time.
+ Later a few more slides follow!

+  CORRECT the following MISTAKE in your Paper Book:
p.185 C5a. '0.016 mm'  should be '0.016 cm' !

timer
15:00

#### Slide 17 -Slide

Up to now ...
The objects (thingies) were drawn much smaller than they are in real life. However, this is going to change!
Fleas (vlooien) or ticks (teken) are seen under a microscope  or in a biology book much greater than they really are.
In that way we can see what they really look like!

A
2 : 8
B
4 : 1
C
1 : 4
D
0.5 : 2

#### Slide 20 -Quiz

So the scale is     4 : 1  ??!
Shouldn't this result be:
1 : 4 ?
No, watch the next slide!

#### Slide 22 -Slide

Did you notice this:
No  matter if the scale is about something smaller or larger than the picture, if possible we always use the number 1 !
So, not          2 : 10    but   1 : 5
However      we write      3 : 2     and  not   1 : 2/3
No fractions or decimal numbers in a scale !
TRY ONE MORE SCALE TASK now.

ANS
timer
1:00

#### Slide 24 -Slide

Solution:
1.  2.75 cm = 27.5 mm
2. 27.5 : 5.5 = 5
3. 5 mm in the drawing
represents 1 mm in reality, so
4.  scale is.  5 : 1

#### Slide 26 -Slide

Homework time
+ Make §5.3 Scale now.

+ Good luck!