Mathematics / Year 8 / Measurement and Geometry / Geometric reasoning

Curriculum content descriptions

Establish properties of quadrilaterals using congruent triangles and angle properties, and solve related numerical problems using reasoning (ACMMG202)

Elaborations
  • establishing the properties of squares, rectangles, parallelograms, rhombuses, trapeziums and kites
  • identifying properties related to side lengths, parallel sides, angles, diagonals and symmetry
General capabilities
  • Literacy Literacy
  • Numeracy Numeracy
  • Critical and creative thinking Critical and creative thinking
ScOT terms

Angles,  Congruence (Geometry),  Quadrilaterals

Text

reSolve: Quarter Cartons

This lesson challenges students to use algebra and proportional reasoning to investigate how changing the size of a paper square or rectangle impacts the dimensions of a box folded from that paper. Students apply knowledge about nets of 3D objects and explore algebraic relationships through a set of hands-on activities ...

Text

reSolve: Polygon Pieces

This lesson explores the geometry of cutting polygons in different ways and using algebra to express subsequent findings. Students use one straight cut to divide a convex polygon into two new polygons. They make generalisations about the total number of sides of the two new polygons, and about the number of different combinations ...

Text

reSolve: Mechanical Linkages: Quadrilaterals

This series of six lessons explores geometry using real world contexts focussed on the dynamics of linkages and moving joints of everyday tools and objects. Students use physical models and computer simulations, the lessons move from a view of geometry as a study static diagrams to encompass movement. Each lesson is outlined ...

Interactive

The geometer's warehouse

This web-based, multimedia resource focuses on the geometry of the Stage 4 and Stage 5 Mathematics syllabus. It comprises 70 dynamic html worksheets, each exploring a different outcome in Stage 4 and Stage 5 geometry.

Text

reSolve: Mathematical modelling: Screentime footprint

In this sequence of four tasks students use linear models to investigate how screen time contributes to carbon dioxide emissions. They consider their personal digital footprint and make predictions about future emissions. Key learning goals, pedagogical tools, illustrations of practice and design decisions for teachers ...

Text

reSolve: Area of a circle

This lesson explores the formula for calculating the area of a circle. Students estimate the area of a circle using inscribed and circumscribed squares, and investigate proofs of the area formula. Each lesson is outlined in detail including curriculum links, vocabulary, materials needed, sample answers, supporting PowerPoint ...

Text

reSolve: Circumference

This sequence of three lessons explores the properties of circles, in particular the relationship between the diameter and circumference. In the first lesson, students use a cylinder containing three tennis balls to understand that a circumference is 'three and a bit' times the diameter. They then complete five different ...

Video

Mystery man Pythagoras meets his match

What do you know about Pythagoras? Join Vi Hart as she not only explains his theorem but raises some legends about his dark past! Follow Vi's timeline of famous mathematicians to find out in which century Pythagoras lived. See how Vi shows a proof of his theorem and raises what was a big dilemma for Pythagoras: the irrational ...

Video

Comparing fuel consumption

Is it more fuel efficient to drive or fly between two places? Watch this clip and learn how to calculate the answer. What are the various factors that need to be taken into account? This video was made using the American measurement of gallons per hour, American firgures for the average number of passengers in a car and ...

Interactive

Desmos Graphing Calculator - Google Play app

Plot functions, create tables, add sliders and animate your graphs. Touch points of interest on the graph to show maximums, minimums and points of intersection. Type in an equation and watch the calculator solve the problem.

Interactive

Syllabus bites – turbo turning

The fourth in a series of Syllabus bites related to transformations on the Cartesian plane. This Bite covers rotation of points.

Video

MathXplosion, Ep 33: On the grid

Explore graphs, grids and mapping with a focus on reading and writing location data using coordinate geometry. Grids and maps illustrate the concepts of parallel/perpendicular lines (axes or labelled number lines), ordered pairs and intersection points.

Video

MathXplosion, Ep 50: How to use a tetrahedron to solve the tree problem

How can you place four trees exactly the same distance apart from one other? By making a model! By using miniature trees to make a model of the problem, it becomes clear that a 2D solution is impossible. We learn how objects can help us visualise the problem situation, which in this case requires a 3D solution: a tetrahedron.

Video

What are pixels?

Meet Kevin Systrom and Piper Hanson as they explain how digital images work. What are pixels, those tiny dots of light, made from? How are colours created and represented? What does Kevin say about the way mathematical functions are used to create different image filters. What is the difference between image resolution ...

Video

Maths inside bees and beehives

Bees are necessary for assisting many plants to produce the food we eat, including meat and milk. Colony collapse disorder, which describes the disappearance of beehives, could have catastrophic effects on food production. Australian scientists are applying their maths and science knowledge to build up a picture of a healthy ...

Interactive

Syllabus bites – mixing it up

The fifth in a series of Syllabus bites related to transformations on the Cartesian plane. This bite covers combinations (composition) of transformations.

Interactive

Syllabus bites – flipping and sliding

This is the third in a series of Syllabus bites related to transformations on the Cartesian plane. Students further their understanding of translation and reflection and explore relationships between these two transformations.

Interactive

Numeracy wrap: Tell me why

Interactive activities that guide students to consider the use and presentation of geometric reasoning.

Video

Are plants mathematicians?

Ever noticed that plants are examples of Fibonacci numbers? Watch Vi Hart draw examples of flower petals and leaf growth that follow this pattern. See how plants seem to use Phi (.), the golden ratio. Find out how to make your own 'angle-a-tron' to create interesting petal designs. This is the second in a series of two.

Interactive

Syllabus bites – speedy sliding

This is the first in a series of Syllabus bites related to transformations on the Cartesian plane aimed at Stage 4 Mathematics. Students find the coordinates of image points after translation. In doing so, they develop fluency in using coordinates and familiarity with the Cartesian plane, providing a basis for the investigations ...