What is a ratio?
The main function of a ratio is to compare or relate numbers.
They are sometimes in the form of Fractions.
For example, 2/3 is a ratio. So is 2:3 and 2 to 3. They all mean the same thing.
The first number(2) is called the antecedent and the second number(3) is called the
consequent.
If you add both the antecedent and the consequent you get the total number.
The total number is 5 (2+3).
You can check the ratios in decimals.
For example: 2/5 or 2 divided by 5=0.4
The antecedent divided by the total number is part of the total number.
3/5 or 3 divided by 5=0.6
The consequent divided by the total number is the other part of the number.
So if you add 0.4 and 0.6 it equals 1, the total number.
You can also do it in percentages
For example:40% + 60% = 100%
Another example is of this picture:
1. In the top left circle, there is a ratios of 1 to 2 of red shaded parts to white parts of the circle.
The total number is 3 because the circle is split into 3 parts.(or 1+2)
2. In the top right circle, there is a ratio of 1 to 1 of red shaded spots to white parts of the circle.
The total number is 2 because the circle is split into 2 parts.(or 1+1)
3. In the bottom circle, there is a ratio of 3 to 3 of green shaded spots to white parts of the circle.
The total number is 6 because the circle is split into 6 parts. (or 3+3)
If you are doing a problem,THE ORDER MATTERS.
For example: The ratio of boys to girls in a class is 13:15
The number of boys in the class would be 13 since it is the first word of the ratio
in the problem. The number of girls would be 15 since it the second word of the
ratio in the problem.
If they asked what is the ratio of boys to the class then you would have to add
the boys and the girls and make it equal 13:28(13+15)
If you are doing a problem that asks "of the 13:28 boys in a class how
many are boys in TMS are there?" heres how:
In a problem like this,they usually include how many people there are in all.
If there are a total of 900 students at TMS, then you ask how do I only find
how many boys there are only with these two numbers. It is actually quite simple .
All you do is multiply 13:28 and 900.
So 13/28(900)=417.85 boys but we cannot have .85 boys so we round up to 418.
The answer would be about 418 boys at TMS.
CLICK AT THE LINK(S) BELOW TO LEARN MORE ABOUT RATIOS:
http://www.purplemath.com/modules/ratio.htm
http://www.mathleague.com/help/ratio/ratio.htm
http://www.math.com/school/subject1/lessons/S1U2L1GL.html