• A ratio compares two quantities of the same kind, measured in the same unit.
• The ratio between the numbers a and b is written a : b or as the fraction a/b.
• The first number a is called the antecedent, and the second number b is called the consequent.
• The order matters the ratio 2 : 3 is not the same as 3 : 2. Only two quantities of the same kind can be compared. If the units are different, change them to one unit first. For example, the ratio of 50 cm to 2 m is not 50 : 2. It is 50 : 200, which equals 1 : 4.
• A ratio is simplified by dividing both terms by a common factor.
• The greatest common factor of 36 and 48 is 12, so 36 : 48 becomes 3 : 4.

Equivalent ratios

1. Two ratios are equivalent when they have the same value. For example
2. 2 : 3 and 6 : 9 are equivalent
3. because 2/3 = 6/9.