Ratio and Proportion

Ratio

What is a ratio?

A Ratio tells us how much of one thing there is compared to another

What do we use Ratios for? How Can We See it Around Us?

Recipes (100ml flour to 1 part salt)

Mixing drinks (1 part cordial to 6 parts water)

Building (4 parts sand to 1 part cement)

Maps (1cm to 1km/mile)

Plans (scale drawings)

Infection Rates (1 person may infect 1.5 other people, etc) (COVID-19)

Sharing Ratios (for example, how do we split $240 in the ratio 3:1)?

Add the Ratio Numbers up (3:1 3+1 = 4)

Divide $240 by 4 = $60

Why four?

Multiply each part of the ratio by $60

Why 60?

3 x 60 = 180, and 1 x 60 = 60 Check the amounts add up correctly ($180 + $60 = $240)