2. We use ratio’s all the time
If you were to go to a restaurant with a
friend, and he ordered twice as much food
as you, would you want to pay half the bill?
We can use ratio’s to share the bill
more fairly.
3. Total parts
Ratio = :
We can find total parts by adding + =
A man uses 3 cans of red paint for every 1 can of
blue, how many total parts?
1 2
1 2 3
Ratio = :3 1
total parts = 4
4. Each part
Ratio = :
Total parts =
If you found out the shape had a height of 50 cm, could we work
out the height of one part?
50cm ÷ total parts
1 4
5
50cm ÷ 5 = 10cm
5. Dividing an amount by a given ratio
Patrick and Emily share £35 in the ratio 3:4
How much does each person get?
First we find the total number of parts: 3 + 4 = 7
Then we find what 1 part is worth: £35.00 ÷ 7 =
1 part = £
so
3 parts = £5 x3
4 parts = £5 x 4
So Patrick gets £ _____and Emily £ ______.
= 15
5
= 20
15 20
6. Dividing an amount by a given ratio
Bill and Todd pay a bill of £80 in the ratio 3:2
How much does each pay?
total number of parts:
Then we find what 1 part is worth:
3 parts = £16 x3
2 parts = £16 x 4
So bill pays £ _____and Todd pays £ ______.
£80 ÷ total parts
£80 ÷ 5 = £16
= £48
= £64
= £48 = £64
7. Divide £ 12 in the ratio 1:3
60 km in the ratio 3:7
£ 45 in the ratio 7:2
Try yourself
Created by Richard Bull
£12 ÷ 4 = £3
1 x £3 = £3
3 x £3 = £9
60km ÷ 10 = 6km
6km x 3 = 18km
6km x 7 = 42km
£45 ÷ 9 = £5
£5 x 7 = £35
£5 x 2 = £10
