Note and Example
What is Ratio?
- Ratio is the comparison of the size or value of one quantity with another.
- It involves comparing two quantities of the same kind.
- These quantities can be the number of objects, measurements of length, weight, or volume.
- Ratios can be simplified.
How to write ratio?
Example: If there are 3 apples and 5 oranges
- The ratio of apples to oranges is 3 : 5.
- The fractional form is .
- Order is important!!! Ratio of apples : oranges ratio of oranges : apples.
- Unit of measurement must be same for both quantities.
Picture1
Example 1A
The table shows the length of fabric purchased by Raysha's mother.
State the ratio:
a) Length of yellow fabric to the length of green fabric.
Answer:
Yellow = 2m
Green = 300cm = 3m
*The unit of measurement must be the same.
Yellow : Geen
2 : 3
| Fabric color | Yellow | Green | Blue |
| Length | 2m | 300cm | 4m |
Example 1B
The table shows the length of fabric purchased by Raysha's mother.
State the ratio:
b) Length of blue fabric to the total length of all fabric.
Answer:
Green = 300cm = 3m
*The unit of measurement must be the same.
Blue = 4m
Total fabric = Yellow + Blue + Green
=2+3+4
=9
Blue : Total fabric
4 : 9
| Fabric color | Yellow | Green | Blue |
| Length | 2m | 300cm | 4m |
Example 1C
The table shows the length of fabric purchased by Raysha's mother.
State the ratio:
c) Total length of all fabric to the length of yellow fabric.
Answer:
Green = 300cm = 3m
*The unit of measurement must be the same.
Yellow=2m
Total fabric = Yellow + Blue + Green
=2+3+4
=9
All fabric : Yellow
9 : 2
| Fabric color | Yellow | Green | Blue |
| Length | 2m | 300cm | 4m |
Picture 2
Example 2a
Based on Picture 2, the mass of each watermelon is the same. State the ratio:
a) the mass of one watermelon to the mass of one pineapple
Answer:
2 watermelon = 4kg
1 watermelon = kg
= 2 kg
1watermelon + 1 pineapple = 3kg
2kg + 1 pineapple = 3kg
1 pineapple = 3kg-2kg
= 1kg
*1 watermelon = 2kg
*1 pineapple = 1kg
1 watermelon : 1 pineapple
2 : 1
Example 2b
Based on Picture 2, the mass of each watermelon is the same. State the ratio:
b) the mass of one pineapple to the total mass of the fruits
Answer:
*1 watermelon = 2kg
*1 pineapple = 1kg
Total mass of fruits = 3 watermelon + 1 pineapple
= 3 x 2kg + 1kg
= 6kg + 1kg
= 7kg
Total fruits : 1 pineapple
7 : 1
Example 3
The price of one pair of pants is 3 times the price of one shirt. State the ratio of the price of one shirt to the total price of one shirt and one pair of pants.
Answer:
1 pants = 3 shirt
Change to fractional form : =
Change to ratio:
* pants : shirt
3 : 1
Total 1 pants + 1 shirt= 3 + 1
= 4
1 Shirt : Total
1 : 4