1. 6.2
Proportions

2. A proportion is a statement that two ratios or rates are equal.
Solving Proportions
A proportion is a statement that two ratios or rates are equal.
If and are two ratios, then
is a proportion. a b c d =

3. Solving Proportions
A proportion contains four numbers. If any three numbers are known, the fourth number can be found by solving the proportion. To solve use cross products. bc a b c d = ad a b c d
Multiply both sides by the LCD, bd
These are called
cross products.
ad = bc
Simplify
cross product

4. Determining Whether Proportions are True?
True proportion

5. Finding Unknown Numbers in Proportions
Cross multiply.
Simplify the left side.
Divide both sides by 28.
Check:
(Rounded)