1. Lesson 6 Ratio’s and Proportions
Solving Equations
Lesson 6
Ratio’s and Proportions

2. Writing ratio’s or Proportions:
Ratio’s are written as part to part in a fraction that is equal to another Ratio.
There are 3 ways to write a ratio: a to b a:b a/b
Proportion: is an equation that states two ratio’s are equivalent.
There are different ways to solve a proportion but we will only use one way for now. It is the way that always works no matter what.
We are going to cross multiply and then solve the equation because both sides are equal to each other.

3. Examples: Ex 1. 8/x = 6/15 cross multiply
6x = divide both sides by 6
X = 20
Ex /x = 8/(x-3) cross multiply
8x = 4x subtract 4x from both sides
4x = divide both sides by 4
X = -3

4. More examples: Ex. 3 3 is to 8 as x is to 32 set up ratio’s
3/8 = x/ cross multiply
8x = divide both sides by 8
X = 12
Ex t is to 4 as (t +8) is to set up ratio’s
T/4 = (t + 8)/ cross multiply
4t + 32 = 8t subtract 4t from both sides
32 = 4t divide both sides by 4
8 = t

5. Homework: Page 165 # 8-18 Page 165 # 23 – 30 Page 171 # 4 – 14