Proportions

Front

What is a proportion?

Back

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

Front

How do you determine if two ratios form a proportion?

Back

Two ratios form a proportion if their cross products are equal.

Front

What is the cross product of the ratios a/b and c/d?

Back

The cross product is ad and bc. If ad = bc, then a/b = c/d.

Front

If a recipe calls for 2 cups of sugar for every 3 cups of flour, what is the ratio of sugar to flour?

Back

The ratio of sugar to flour is 2:3.

Front

How do you solve for x in the proportion 4/x = 2/3?

Back

Cross multiply to get 4*3 = 2*x, which simplifies to x = 6.

Front

What is the unit rate?

Back

The unit rate is a comparison of two different quantities when they are combined together, expressed as a quantity per one unit.

Front

If 5 apples cost $10, what is the cost of one apple?

Back

The cost of one apple is $2.

Front

In a scale drawing, if 1 inch represents 5 feet, how many feet does 3 inches represent?

Back

3 inches represents 15 feet.

Front

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

Back

If a/b = c/d, then ad = bc. You can solve for the missing value using this formula.

Front

If a car travels 150 miles in 3 hours, what is its speed in miles per hour?

Back

The speed is 50 miles per hour.