New
New
Inverse proportion in context
I can recognise inverse proportion graphically and use inverse proportionality in a range of contexts.
Lesson 15 of 16
New
New
- Year 8
Inverse proportion in context
I can recognise inverse proportion graphically and use inverse proportionality in a range of contexts.
Lesson details
Key learning points
- Inverse proportion can be represented on a graph.
- Key features can be used to recognise inverse proportion on a graph.
- Inverse proportion can be used in a number of contexts.
Keywords
Inverse proportion - Two variables are inversely proportional if there is a constant multiplicative relationship between one variable and the reciprocal of the other.
Common misconception
The graph representing a inversely proportional relationship is of the form x + y = a and will eventually meet the axes.
The dimensions of the rectangle are ideal for highlighting this, particularly the latter part as a you cannot have a rectangle with a length of 0 cm.
Use a dynamic graphing package to show the area of the rectangle problem. Question: 'Can I have a rectangle with a width 0f 0.005cm?' you can use the graph to show that you can.
Teacher tip
Licence
This content is © Oak National Academy Limited (2025), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).
Lesson video
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Prior knowledge starter quiz
6 Questions
Q1.Two variables are in proportion if they have a __________.
Two variables are in proportion if they have a __________.
constant additive relationship
changing multiplicative relationship
different relationship
changing additive relationship
Q2.5 miles = 8 kilometres. So 12 miles is kilometres.
5 miles = 8 kilometres. So 12 miles is kilometres.
Q3.Convert 1 m³ into cm³.
Convert 1 m³ into cm³.
1000 cm³
10 000 cm³
100 000 cm³
1 000 000 cm³
Q4.The cost of a box of pens is £4.80. Five boxes of pens cost £ .
The cost of a box of pens is £4.80. Five boxes of pens cost £ .
Q5.If $20 = £15.20, which of the following are true?
If $20 = £15.20, which of the following are true?
$100 = £95.20
$10 = £5.20
Q6.A recipe needs 180 ml of milk to make 15 scones. You can make scones using 15 litres of milk.
A recipe needs 180 ml of milk to make 15 scones. You can make scones using 15 litres of milk.
Assessment exit quiz
6 Questions
Q1.Two variables are inversely proportional if there is a constant multiplicative relationship between one variable and the __________ of the other variable.
Two variables are inversely proportional if there is a constant multiplicative relationship between one variable and the __________ of the other variable.
different
division
opposite
Q2.Which of the following is a graph representing inverse proportion?
Which of the following is a graph representing inverse proportion?
Q3.Which of the following situations illustrate an inversely proportional relationship?
Which of the following situations illustrate an inversely proportional relationship?
The number of scones made and the amount of milk needed.
The time taken to read a book and the number of pages.
The height of a wall and the number of bricks used.
Q4.A and B are inversely proportional. The missing value is .
A and B are inversely proportional. The missing value is .
Q5.A and B are inversely proportional. The missing value is .
A and B are inversely proportional. The missing value is .
Q6.It takes 3 people 4 days to build a wall. It should take 5 people days to build the same wall.
It takes 3 people 4 days to build a wall. It should take 5 people days to build the same wall.
