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Ratio and Proportion
- Always simplify as low as possible.
- Always convert to common units when working out.
- Remove units in final answer.
When it comes to IGCSE/GCSE Maths, can you calculate the ratio of two different units?
- E.g. 500p : £15
- common unit ⟶ £5 : £15
- simplify ⟶ £1 : £3
- final answer ⟶ 1 : 3
Compound Measures
- Involves 3 variables.
- These can be connected by a triangle.
- E.g. Pay ⟶ hours worked × rate per hour
- P = H × R
- H = P/R
- R = P/H
![broken image](http://custom-images.strikinglycdn.com/res/hrscywv4p/image/upload/c_limit,fl_lossy,h_9000,w_1200,f_auto,q_auto/4936730/44592_995033.png)
![broken image](http://custom-images.strikinglycdn.com/res/hrscywv4p/image/upload/c_limit,fl_lossy,h_9000,w_1200,f_auto,q_auto/4936730/350554_901811.png)
Unit Changes
- 1m = 100 cm
- 1m² = 10,000cm (100 × 100)
- 1m³ = 1,000,000 cm³ (100 × 100 ×100)
- 1cm² = 100mm²
- 1m² = 10,000 cm²
- 1km² = 1,000,000 m²
- 1cm³ = 1,000 mm³
- 1m³ = 1,000,000 cm³
- 1km³ = 10⁹ m³
- If you go down a unit --> multiplication ×.
- If you go up --> division ÷.
![broken image](http://custom-images.strikinglycdn.com/res/hrscywv4p/image/upload/c_limit,fl_lossy,h_9000,w_1200,f_auto,q_auto/4936730/317232_550170.png)
That's the end of the topic!
![broken image](http://custom-images.strikinglycdn.com/res/hrscywv4p/image/upload/c_limit,fl_lossy,h_9000,w_1200,f_auto,q_auto/4936730/961174_508843.jpeg)
Drafted by Bonnie (Mathematics)