Percent Proportions

A percent proportion is a mathematical equation that shows the relationship between a part, a whole, and a percentage. It is often expressed as $$\frac{part}{whole} = \frac{percent}{100}$$ .

To find a percentage of a number, multiply the number by the percentage (in decimal form). For example, to find 20% of 50, calculate $$50 \times 0.20 = 10$$ .

The formula to calculate percent grade is $$\frac{earned\ points}{total\ points} \times 100$$ .

This can be expressed as $$\frac{x}{250} = \frac{90}{100}$$ , where x is the unknown number.

To find 28% of 63, calculate $$63 \times 0.28 = 17.64$$ .

To convert a fraction to a percentage, divide the numerator by the denominator and multiply by 100. For example, $$\frac{1}{4} = 0.25 \times 100 = 25$$ .

The relationship is defined by the equation $$\frac{part}{whole} = \frac{percent}{100}$$ .

Set up the equation as $$\frac{75}{150} = \frac{x}{100}$$ , where x is the unknown percentage.

If a number is 120% of another number, it means it is 1.2 times that number. For example, if x is the number, then 120% of x is $$1.2x$$ .

To find what percent one number is of another, divide the first number by the second number and multiply by 100. For example, to find what percent 75 is of 150, calculate $$\frac{75}{150} \times 100 = 50$$ .