**1. Ratio**

- Meaning of ratio – Given any two similar quantities, a and b, the ratio of a to b (denoted by a:b) is defined as a:b = a/b, where b != 0
- The quantities have to have same/similar unit.
- Simplification of ratios: a:b = (ma): (mb) = (a/m): (b/m), where m !=0

**2. Ratios of three quantities**: the ratio involving three quantities cannot be written as a fraction. However, it can be simplified by multiplying or dividing each term by the same constant. For example, a:b = 5:6, b:c = 8:11, find a:b:c. Recall LCM, we convert each ratio to an equivalent ratio where the new value of b is the LCM of the original values of b:

a:b = 5:6 = 5*4 : 6*4 = 20:**24**

b:c = 8:11 = 8*3 :11*3 = **24**:33

hence , a:b:c = 20:**24**:33

**3. Word problems involving ratios**

**4. Home Work:**

- Handout:
- two page

- Page 33:
- 1, 2, 3, 4