http://www.mathgoodies.com/lessons/percent/proportions.html
this website helped me ! =]
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To find a percent.
100
A percent is simply a proportion out of 100.
Like this if your looking for say 13 percent of 200 you need to set it as 13 over 100 and then x over 200. Then cross mulitply 13x200 then divide that by 100 and you get your answer.
You can use the equivalent form of the percent proportion, which is expressed as ( \text{part} = \text{percent} \times \text{whole} ), to solve percent problems by identifying the part (the amount you want to find), the percent (the percentage given), and the whole (the total amount). By rearranging the formula, you can solve for the unknown variable. For example, if you need to find 20% of 50, you can calculate it as ( \text{part} = 0.20 \times 50 ), leading to the solution of 10.
32
A simple tool to remember is: IS over OF equals percent over 100.If we put this into a proportion, we get:IS/OF = percent/100.Just put all percent problems into this format, and solve the proportion.Example: 12.5 IS what percent OF 75?Or,12.5 IS | what percent | OF 75?Just put these numbers into the proportion: (We will use x for the percent, as that is the unknown we are solving for)12.5/75 = x/100.Then solve by cross multiplying:75x = 1250.Then divide by 75:x = 1250/75,x = 16 2/3 %
There is no "should" or "should not". The depends on the question that you are trying to answer.
Use a proportion.- x/63.2=16/100 100x=16x63.2 100x/100=1011.2/100 x=10.112
7/29=M/100
To solve ratio, proportion, and percent problems, first convert the problem into a fraction if necessary. For percentages, express the percent as a decimal (e.g., 25% as 0.25) and then apply it to the relevant quantity. Use cross-multiplication for proportions to find unknown values, and remember that the formula for percent is: Percent = (Part/Whole) × 100. Finally, ensure to simplify your answers where possible for clarity.