B2.8 Compare proportional situations and determine unknown values in proportional situations, and apply proportional reasoning to solve problems in various contexts.
Activity 1: It's a Question of Speed (Comparing Proportional Situations and Converting Units)
In teams of 2, students research the units and transform the ratios to compare them. They must :
Rank the following speeds in increasing order. Demonstrate their approach and calculations.
- 15 km/h
- 230 cm/s
- 9 m/min
- 27 dam/s
Activity 2: It is Proportional (Finding the Unknown Value)
Present a series of problems where proportional reasoning is to be applied to solve them. Note the strategies used by the students. Take pictures of particularly interesting approaches. Review with the class.
Examples of problems
- Sofia runs 60 km in 15 minutes. She maintains this pace during the race. How far will she run in one hour? Demonstrate your strategy.
- A company manufactures tour bags with five storage pockets each. How many pockets will there be in 60 bags?
- The Vida company designs emergency bags that include 12 long and five small bandages. If there are 144 long bandages, how many small ones are there?
- A company sells bags of coloured candy. No matter how big the bags are, there are always three blue candies for every five green ones. If there are 72 blue candies in a bag, how many green candies are there?
- If Pablo saves twenty dollars every time he accumulates fifty dollars, how much will he have saved if he has managed to accumulate seven hundred and fifty dollars?