This lesson about proportions will teach you some very important concepts you need to know. You should review the lesson about ratio before studying this lesson.
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Take a look at the image above. Try to measure the ratio of arm's length to height for 5 people that you know. What did you notice? More on this later, so keep reading!
Definition:
Simply put, whenever we put an equal sign between two ratios and the ratio on the left is equal to the ratio on the right, we say that they form a proportion.
3
5
|
and
6
12
|
3
5
|
=
6
12
|
3
5
= 0.60
|
6
12
= 0.5
|
The cross products for
3
5
|
and
6
12
are
|
36 is not equal to 30. Therefore,
3
5
|
and
6
12
do not form a proportion
|
Another example: Do
10
16
|
and
5
8
form a proportion ?
|
If
a
b
|
=
c
d
is a proportion
|
3
5
|
and
6
12
|
3
5
|
=
6
12
|
3
5
= 0.60
|
6
12
= 0.5
|
The cross products for
3
5
|
and
6
12
are
|
3
5
|
and
6
12
do not form a proportion
|
Do
10
16
|
and
5
8
form a proportion ?
|
If
a
b
|
=
c
d
is a proportion
|
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Nov 18, 20 01:20 PM
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