3-2 Percent Proportions Flashcard Review

Front

What is a percent?

Back

A percent is a way of expressing a number as a fraction of 100. It is denoted by the symbol '%'. For example, 25% means 25 out of 100.

Front

How do you calculate a percentage of a number?

Back

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

Front

What is the formula to find the total amount from a percentage?

Back

The formula is: Total Amount = (Part / Percentage) x 100. For example, if 30 is 20% of a total, then Total Amount = (30 / 0.20) = 150.

Front

How do you find the percentage increase?

Back

To find the percentage increase, use the formula: ((New Value - Old Value) / Old Value) x 100. For example, if a price increases from $50 to $60, the increase is ((60 - 50) / 50) x 100 = 20%.

Front

What is a proportion?

Back

A proportion is an equation that states that two ratios are equal. For example, if a/b = c/d, then a, b, c, and d are in proportion.

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How do you solve a proportion?

Back

To solve a proportion, cross-multiply and then divide. For example, if a/b = c/d, then ad = bc, and you can solve for the unknown.

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What is the relationship between fractions and percentages?

Back

Fractions can be converted to percentages by multiplying by 100. For example, 1/4 = 0.25, which is 25%.

Front

How do you find the percentage of a total?

Back

To find the percentage of a total, divide the part by the total and multiply by 100. For example, if 15 out of 60 students passed, the percentage is (15/60) x 100 = 25%.

Front

What is a tax rate?

Back

A tax rate is the percentage at which an individual or corporation is taxed. For example, if the tax rate is 8%, then for every $100 earned, $8 is paid in taxes.

Front

How do you calculate sales tax?

Back

To calculate sales tax, multiply the price of the item by the sales tax rate (in decimal form). For example, for a $50 item with an 8% tax rate, the tax is 50 x 0.08 = $4.