Mathematics / Year 9 / Number and Algebra / Real numbers

Curriculum content descriptions

Solve problems involving direct proportion. Explore the relationship between graphs and equations corresponding to simple rate problems (ACMNA208)

Elaborations
  • identifying direct proportion in real-life contexts
General capabilities
  • Literacy Literacy
  • Numeracy Numeracy
  • Critical and creative thinking Critical and creative thinking
ScOT terms

Rates (Ratios),  Linear equations,  Direct proportions,  Gradients

Interactive

Syllabus Bites: Proportionality problems

This is the fourth in a series of Syllabus Bites related to direct and indirect proportion. Students use graphs, equations and numerical methods to solve problems involving direct proportion.

Interactive

Syllabus Bites: Direct proportion

This is the second in a series of Syllabus Bites related to direct and indirect proportion. Interactive applets and dynamic geometry software allow students to explore quantities in direct proportion. Students draw conclusions about relationships between the variables and consolidate their understanding by playing a simple game.

Interactive

Syllabus Bites: Revisiting proportion

This is the first in a series of Syllabus Bites related to direct and indirect proportion. Students revise the concept of ratio. They create short visual explanations showing how problems can be solved.

Interactive

Syllabus Bites: Graphing direct proportion

This is the third in a series of Syllabus Bites related to direct and indirect proportion. Students draw graphs to represent relationships between variables in direct proportion. They associate the gradient of the graph with the constant of proportionality. They investigate practical contexts that give rise to direct proportion.

Interactive

Sites2See – applied mathematics

This collection of resources for Applied Mathematics has helpful links for the six Focus Studies - Communication, Driving, Design, Household Finance, Human Body and Personal Resource Usage. A laptop-friendly resource.

Online

TIMES Module 35: Number and Algebra: proportion - teacher guide

This is a 22-page guide for teachers. The module introduces the idea of direct proportion and illustrates its many uses in science, commerce and measurement. It looks at ratios, gradients and fractions. A history of the development and use of proportion concludes the module.

Video

Catalyst: Nautical Robots

How might you find out how much and where the Earth's oceans are warming? Watch the report by Ruben Meerman and discover how more than 3000 'nautical robots', known as argo floats, have been placed in the oceans to collect data on variations in temperature, pressure and salinity.

Downloadable

Different ways to pay

This lesson challenges students to explore the pros and cons of various payment options, how they spend their money, different consumer products and where to go for more information about saving money and debt. During the lesson, students investigate multiple payment options to choose those that suit their circumstances, ...

Downloadable

The cost of cars

This lesson is designed for students to learn about car ownership in Australia and the real costs of buying and running a car. Students explore car ownership statistics in Australia, investigate the range of decisions people make about transport, calculate and compare costs of transport and make decisions on additional ...

Online

Mathematical modelling (Measurement): Year 9 – planning tool

This planning resource for Year 9 is for the topic of Mathematical modelling. Students continue to solve mathematical problems from the real world around them. They draw upon knowledge learnt in the area of Measurement.

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A Little Atmosphere

This activity invites students to model the scaled thickness of the atmosphere on a globe using sheets of transparency material. The activity includes a list of tools and materials required, what to do and notice, an explanation for the underlying science of what students observe and suggestions for further activities.

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Indigo Interior

This resource is a web page containing a problem solving task that requires an understanding of Pythagoras' theorem. The task involves finding the area of shaded region with a circle with a known area. To solve the problem students need to establish a right angled triangle and apply Pythagoras' theorem. A printable resource ...

Online

reSolve: Tree Biomass

In this sequence of two lessons, students investigate how many trees would be required to supply paper for their school for a year. Students use similar triangles, Pythagoras' Theorem and algebra to design and construct a Biltmore stick, used to measure the diameter and height of a tree. They measure trees, calculate their ...

Video

My Five Cents: What is opportunity cost?

What is the true cost of buying something? Gen Fricker explains that it's more than just money. Learn about opportunity cost - what it is, why it's a helpful tool and when to use it. Simple! Then test yourself with ASIC MoneySmart's "Things to think about" classroom exercises.  

Online

reSolve: Rectilinear Polygons

In this sequence of three lessons, students use geometric reasoning to establish relationships between angles in polygons and go on to make generalisations using algebraic expressions. Students explore and enumerate right angles in a series of rectilinear polygons and generalise their findings. They then explore the number ...

Online

reSolve: Gradient and Tangent

This sequence of two lessons investigates gradient and angle by applying the tangent ratio to find the angles represented by a road sign or the angle of a street. In the first lesson, students research what a road grade is and determine the actual angle of a road given its grade. They then construct their own road sign ...

Online

reSolve: Pythagoras' Theorem - Lunch Lap

In this sequence of two lessons, students apply Pythagoras' Theorem to explore a practical problem involving optimising paths to lunch carts. In the first lesson, students investigate the length of a path that touches three sides of a rectangle, starting and finishing at the same point. They model the problem, use Pythagoras' ...

Online

reSolve: Mechanical Linkages: Similar Triangles

This sequence of lessons explores the geometry of similar triangles using two real world objects: ironing boards and pantographs. In the first lesson, students investigate different ironing board leg lengths and pivot positions using similar and congruent triangles. In the second lesson, they use their knowledge of parallelogram ...

Online

reSolve: Monte Carlo Simulations

This sequence of two lessons explores how statistical techniques that rely on randomly generated data can be used to solve problems. In the first lesson, students compare different methods for calculating the area of an irregular shape, using the context of oil spill maps. They are introduced to the Monte Carlo method for ...

Video

My Five Cents: Why investing can be risky

Planning to get rich quick by investing one day? Before you jump in, let Gen Fricker explain some of the risks involved with different types of investments. Then test yourself with ASIC MoneySmart's "Things to think about" classroom exercises.