1 Press Ctrl-A ©G Dear 2010 – Not to be sold/Free to use Applied Mathematic (Preliminary General 1) Ratios Stage 6 - Year 11

2 A ratio is a comparison of two (or more) quantities of the same type. Do men need to worry about getting married? Sex Ratio (Men:Women) 50: : :100 Source: ABS (2009)

3 Scale = 1:100 Ratio Building

4 Scale = 1:150 Ratio Building

5 Television in the context of measurement. Analogue Width : Height 4: Width : Height 16:9 Digital

6 Cooking Making Pancakes : : 1egg : 1 cup : 1.5 cup FlourMilk Mistake These are different types of quantities. Therefore not a ratio.

7 Sport Bicycle Gearing 17:40 Ratio

8 8 A ratio compares two quantities of the same type. 100cm to 25cm to 15cm Ratios can be simplified by dividing all numbers by the HCF. 100:25:15HCF = 5 ÷5 ÷5 ÷5 20:5:3

g:6000 g Simplify 500g:6Kg 500:6000 5:60 1: kg:600 kg Simplify 3t:600kg 3000:600 30:6 5:1 To be compared all quantities need to be in the same units.

10 To divide a quantity in a given ratio we: E.g. Divide $60 in the ratio 5:7. 1. Calculate the value of one share. 2. Calculate each part of the ratio. 12 shares = $60 1 share = $5 ÷12 5 shares = 5 x $5 = $25 7 shares = 7 x $5 = $35