FreeAlgebra Tutorials!

Try the Free Math Solver or Scroll down to Tutorials!

 Depdendent Variable

 Number of equations to solve: 23456789
 Equ. #1:
 Equ. #2:

 Equ. #3:

 Equ. #4:

 Equ. #5:

 Equ. #6:

 Equ. #7:

 Equ. #8:

 Equ. #9:

 Solve for:

 Dependent Variable

 Number of inequalities to solve: 23456789
 Ineq. #1:
 Ineq. #2:

 Ineq. #3:

 Ineq. #4:

 Ineq. #5:

 Ineq. #6:

 Ineq. #7:

 Ineq. #8:

 Ineq. #9:

 Solve for:

 Please use this form if you would like to have this math solver on your website, free of charge. Name: Email: Your Website: Msg:

# Working with Percentages and Proportions

When working with percentages, it is often helpful to think of them in terms of ratios and proportions. For instance, if someone asks you, â€œWhat is 10% of 40?â€ you could simply change 10% into a decimal (0.1) and multiply it by 40 to get 4. But what if you were asked, â€œ5% of what number is 10?â€ Thatâ€™s a little trickier. To do this calculation, it is convenient to use a proportion.

PROCEDURE: To use percentages in a proportion, first put your known percentage in a ratio with 100. Then create an equivalent ratio, leaving the place for your unknown quantity blank. Cross-multiply the known numerator with the known denominator. Divide the product with your remaining known value. The result is your unknown quantity.

SAMPLE PROBLEM: 25% of what number is 4?

 Step 1: Put your percentage in a ratio with 100. Step 2: Create an equivalent ratio, leaving the space for the unknown quantity blank. Step 3: Cross-multiply the known numerator with the known denominator. Step 4: Divide the product with the remaining known quantity.

25% of 16 is 4.