Proportions and ratios, oh my!

Front

What is a ratio?

Back

A ratio is a comparison of two quantities, showing how many times one value contains or is contained within the other.

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

If 190 people fit in 3 buses, how many people fit in one bus?

Back

63.33 people per bus.

Front

If 570 people need to be transported and each bus carries 63.33 people, how many buses are needed?

Back

9 buses.

Front

What is the constant of proportionality?

Back

The constant of proportionality is the constant ratio between two proportional quantities.

Front

If 13 out of 20 homes have a personal computer, what is the ratio of homes with computers to total homes?

Back

The ratio is 13:20.

Front

How do you find the expected number of homes with computers on a street with 60 homes?

Back

Use the ratio: (13/20) * 60 = 39 homes.

Front

What does it mean if two ratios do not form a proportion?

Back

It means that the cross products of the ratios are not equal.

Front

If selling 5 phones earns $215, what is the constant of proportionality?

Back

The constant of proportionality is $43 per phone.