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 the 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 is a proportion.

Front

What is a proportional relationship?

Back

A proportional relationship is one where two quantities maintain a constant ratio.

Front

What does it mean for a graph to be proportional?

Back

A graph is proportional if it is a straight line that passes through the origin.

Front

If 4 pounds of apples cost $8, how much do 10 pounds cost?

Back

$20 (10 pounds = 4 pounds x 2.5, so $8 x 2.5 = $20).

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 equation.

Front

What is the unit rate?

Back

The unit rate is the ratio of two measurements in which the second term is 1.

Front

If a car travels 300 miles in 5 hours, what is the unit rate of speed?

Back

60 miles per hour (300 miles ÷ 5 hours = 60 miles/hour).

Front

What is the constant of proportionality?

Back

The constant of proportionality is the constant ratio in a proportional relationship.