Understanding Proportions

1
Understanding Proportions

• Lesson 6-3

2
Vocabulary

• A proportion is an equation stating that two
  ratios are equal.

To prove that two ratios form a proportion, you
must prove that they are equivalent. To do this,
you must demonstrate that the relationship
between numerators is the same as the
relationship between denominators.
3
Examples Do the ratios form a proportion?
x 3
Yes, these two ratios DO form a proportion,
because the same relationship exists in both the
numerators and denominators.
7
21
,
10
30
x 3
4
8
2
,
No, these ratios do NOT form a proportion,
because the ratios are not equal.
9
3
3
4
Completing a Proportion

• Determine the relationship between two numerators
  or two denominators (depending on what you have).
• Execute that same operation to find the part you
  are missing.

5
Example
5
35
7

40
8
5
6
Homework Time