Proportions Word Problems Review

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.

Front

How do you solve a proportion?

Back

To solve a proportion, cross-multiply the terms and then solve for the unknown variable. For example, if \( \frac{a}{b} = \frac{c}{d} \), then you can solve it by calculating \( a \cdot d = b \cdot c \).

Front

What is the formula for finding a missing value in a proportion?

Back

The formula is \( \frac{a}{b} = \frac{c}{x} \), where x is the unknown. Cross-multiply to find x: \( a \cdot x = b \cdot c \).

Front

If a recipe calls for 2 cups of sugar for every 3 cups of flour, how much sugar is needed for 9 cups of flour?

Back

6 cups of sugar. (Set up the proportion: \( \frac{2}{3} = \frac{x}{9} \) and solve for x.)

Front

What is the scale of a map?

Back

The scale of a map is the ratio of a distance on the map to the actual distance on the ground. For example, a scale of 1 cm : 10 km means 1 cm on the map represents 10 km in reality.

Front

How do you set up a proportion for a map scale problem?

Back

To set up a proportion, use the format \( \frac{map\ distance}{actual\ distance} = \frac{map\ distance\ to\ find}{actual\ distance\ to\ find} \).

Front

If 4 apples cost $2, how much do 10 apples cost?

Back

$5. (Set up the proportion: \( \frac{4}{2} = \frac{10}{x} \) and solve for x.)

Front

What is a unit rate?

Back

A unit rate is a comparison of two different quantities when they are combined together. It is often expressed as a quantity per one unit of another quantity.

Front

How do you find the unit rate from a proportion?

Back

To find the unit rate, divide the numerator by the denominator. For example, if 4 apples cost $2, the unit rate is \( \frac{2}{4} = 0.5 \) dollars per apple.

Front

What is the relationship between ratios and proportions?

Back

Ratios compare two quantities, while proportions state that two ratios are equal. For example, if the ratio of boys to girls is 2:3, the proportion can be written as \( \frac{2}{3} = \frac{4}{6} \).