Percentages as Comparisons
Date: 11/18/98 at 21:41:30 From: Dyana Goldman Subject: How do you find what percent 45 is of 82? How do you find what percent 45 is of 82? I looked at your site and saw that someone had asked the same question, except they asked what percent 27 is of 76. I did not at all understand the explanation. Could you help me?
Date: 12/22/98 at 11:27:30 From: Doctor Matthew Subject: Re: How do you find what percent 45 is of 82? That's a good question! What exactly is a percentage? You can think of it as the concept of "how big one thing is compared to another." This sounds funny, but it's what a percentage is. So if item A is 100% of item B, then items A and B are the same "size." (Remember that percentages are in units of 100, so anything less than 100 is smaller, and anything more than 100 is larger). When we say (for example) that a number is 50% of another number, we know that the first number is half the second. Let's deal with a more complicated example. Pretend that you have 4 of your friends with you, 3 of them have brown hair, and 1 of them has red hair. You want to know what percentage of your friends has red hair. (Here's part of your answer: it's almost always easier to find out the fraction part first, and then do the percentage). You have a total of 4 friends, and only 1 with red hair, so the percentage is 1/4 (percentage-fractions work like this, you put the number of the thing you want to find on the top, and the total number on the bottom). To find the percentage, you do the following, long divide the fraction that you find (in our case 1/4, which works out to be .25), then multiply it by 100, and that's your percentage (25%). Now to find the fraction that the percentage is, it's also very simple. The numerator of the fraction (remember that's the top part) is the number of the percentage (25) and the denominator is 100. So the fraction is 25/100, which we know we can reduce to 1/4. So there's your answer! I hope this helps! - Doctor Matthew, The Math Forum http://mathforum.org/dr.math/
Search the Dr. Math Library:
Ask Dr. MathTM
© 1994- The Math Forum at NCTM. All rights reserved.