7th grade - Ratios

RATIOS tell how one number is related to another number.

A ratio may be written as A:B or A/B or by the phrase "A to B".

A ratio of 1:5 says that the second number is five times as large as the first.

The following steps will allow determination of a number when one number and the ratio between the numbers is given.

Example: Determine the value of B if A=6 and the ratio of A:B = 2:5

• Determine how many times the number A is divisible by the corresponding portion of the ratio. (6/2=3)
• Multiply this number by the portion of the ratio representing B (3*5=15)
• Therefore if the ratio of A:B is 2:5 and A=6 then B=15