1. A proportion is an equation that states two ratios are equal
Proportions
A proportion is an equation that states two ratios are equal

2. Ratios: to 8 and 9 to 12
Proportion
6 = 9
The cross product of proportions are always equal
For instance 6 x 12 = 72 and 8 x 9 = 72

3. Ratios: 5: 9 and 15: 27
Proportion
5 = 15
The cross product of proportions are always equal
For instance 5 x 27 = 135 and 9 x 15 = 135

4. Which pairs could form a proportion?
3 = 6
6 = 4
4 = 5
8 x 6 = 48
3 x 16 = 48 YES
6 x 6 = 36
4 x 9 = 36 YES
4 x 9 = 36
5 x 8 = 40 NO

5. Solving Proportions: cross multiply
25 = x
35 x = 175
X = 5
N = 20
50n = 300
N = 6
3.6 = n
360 = 200n
1.8 = n