7.CE.2 Proportions

Front

What is a proportion?

Back

A proportion is an equation that states that two ratios are equal.

Front

How do you find a percentage of a number?

Back

To find a percentage of a number, multiply the number by the percentage (in decimal form). For example, to find 25% of 80, calculate 80 * 0.25 = 20.

Front

What is the formula to find the total when given a part and a percentage?

Back

The formula is: Total = Part / (Percentage in decimal form). For example, if 8 is 40% of a number, the total is 8 / 0.4 = 20.

Front

What does it mean for two ratios to form a proportion?

Back

Two ratios form a proportion if they can be set equal to each other, meaning they represent the same relationship.

Front

If 150 grams of fertilizer is needed for 6 acres, how much is needed for 1 acre?

Back

To find the amount needed for 1 acre, divide 150 grams by 6 acres, which equals 25 grams per acre.

Front

How do you solve for an unknown in a proportion?

Back

Cross-multiply the ratios and then solve for the unknown. For example, if a/b = c/d, then a*d = b*c.

Front

What is 40% of 50?

Back

40% of 50 is calculated as 50 * 0.4 = 20.

Front

How do you convert a fraction to a percentage?

Back

To convert a fraction to a percentage, divide the numerator by the denominator and multiply by 100. For example, 1/4 = 0.25 * 100 = 25%.

Front

What is the relationship between ratios and proportions?

Back

Ratios compare two quantities, while proportions show that two ratios are equivalent.

Front

If 15 is what percent of 75, how do you find the percentage?

Back

To find the percentage, use the formula: (Part/Whole) * 100. So, (15/75) * 100 = 20%.