Tuesday, January 20, 2009

Change A Fraction Into A Percentage

Converting fractions to percentages can be done a few ways.


Changing fractions into percentages is like riding a bike: Once you learn do it, you'll remember it forever. There are a few quick tips to learn to help you make your conversion. Once you catch on to those, you can really master the conversion skill.


Instructions


1. Know what a fraction is. A fraction is an expression of a number. It has a numerator (the number on top) and a denominator (the number on the bottom). They are not by themselves percentages, but they can easily be converted into one with some simple mathematical skills.


2. Multiply the fraction by 100 to get the percentage. For example, take the fraction 1/2. Multiply 1/2 by 100/1 and it equals 100/2. Divide 100 by 2 and it equals 50. The percentage that is equal to 1/2 is 50 percent.


3. Find the lowest common denominator. Sometimes you will know the percentage of a fraction but you will not recognize it. For example, what percentage makes up the fractions 45/60, 96/768 and 140/560? They are the same as 3/4, 1/8 and 1/4: it's just harder to see at first glance. To find the lowest common denominator, divide each number in the fraction by the same number. Using the 45/60 example, you can see that both numbers can be divided by 15. This reduces the fraction to 3/4 or 0.75, which equals 75 percent.


4. Cross-multiply the fractions. If you have a difficult fraction like 9/16, write down x/100 right next to it on a piece of paper and cross-multiply (the x is for the percentage that you are trying to find). So multiply 9 times 100 and x times 16). You now have an equation that looks like 16x = 900. Divide both sides by 16 to get the equation x = 900/16. Get out the calculator and you will find that the answer is 56.26 percent.

Tags: common denominator, lowest common, lowest common denominator, percentage that