Mathematics / Year 8 / Measurement and Geometry / Geometric reasoning

View on Australian Curriculum website Australian Curriculum, Assessment and Reporting Authority
Curriculum content descriptions

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

  • 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

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Year level 7-8
Resource type
Learning area Mathematics
Interactive resource

HOTmaths: exploring kites

Use a tool to explore and identify the properties of kites. For example, investigate angles, side lengths and the lengths of diagonals in kites.


BBC Bitesize: 2-D shapes - revision

This is a collection of information sheets on the geometrical properties of special quadrilaterals and 2-D representations of 3-D shapes. Students have access to a multiple-choice test to assess their knowledge of quadrilaterals and representations of 3-D shapes. This resource is one of a series of online resources from ...

Interactive Resource

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.

Teacher resource

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 Resource

The Mathematical Toolkit

A 2D Shapes tool that can be used to create geometric objects such as quadrilaterals, circles, triangles, lines, arcs, rays, segments and vectors on a coordinate grid. Plot and label the vertices to reveal the internal angles, side lengths, area and perimeter, then manipulate the shapes on a grid to transform their shape ...

Interactive Resource

Numeracy wrap: Parallelogram peculiarities

Interactive activities that guide students to investigate properties of parallelograms.

Interactive resource

Exploring quadrilaterals

Examine the sides and angles of a four-sided shape. Identify its geometric properties such as the number of sides of equal length. Classify the shape as a parallelogram, rhombus, square, rectangle, kite or trapezium. Notice that some quadrilaterals can be classified in different ways.

Interactive resource

Congruent triangles

Find out about congruent and non-congruent triangles and the conditions required to make them. Use line segments and angles to build two congruent triangles for three different combinations of sides and angles. Explore the SSS case (side, side, side), the SAS case (two sides and the included angle) and the ASA case (two ...


Geometric reasoning - congruence

This is a website designed for both teachers and students that introduces congruence of shapes in the plane through transformations. In particular, transformations, translations, reflections in an axis and rotations of multiples of 90 degrees are used to define congruence and to identify congruent shapes. The four congruence ...

Interactive resource

Exploring triangles

Find an active triangle in a photograph. Work out its angles by applying principles of opposite angles, complementary angles, supplementary angles and the sum of interior angles. Watch a video showing how triangles are used in buildings and other structures.

Interactive Resource

Planes of Symmetry

An animated tutorial demonstrating planes of symmetry of solids. An interactive quiz is included.

Interactive resource

Exploring ratios and proportions

Explore ratios by comparing the dimensions of two rectangles. Choose a scale to enlarge the smaller shape and identify whether its sides are proportional to those of the larger rectangle. For example, a rectangle with sides in the ratio 4:5 has an equivalent ratio to a rectangle with sides in the ratio 12:15. Watch a video ...

Interactive Resource

Renovate, Calculate!

A student resource that explores the use of mathematics in the trades. Highly interactive investigations into ratio, areas of special quadrilaterals and right-angled trigonometry.

Interactive resource

Exploring trigonometry

Label the three sides of a right-angled triangle as hypotenuse, adjacent and opposite sides. Identify which sides form a trigonometric ratio such as cosine or tangent. Watch a video showing how trigonometry is used to help planes land safely.


Symmetry and pattern: the art of oriental carpets

This resource is a website about the study of symmetry through analysing patterns in oriental carpets. It presents a gallery of different oriental rugs. Details about the patterns in each rug can be accessed by selecting the image of the rug or the key below the images. There are links to pages that explain symmetry and ...

Moving Image

Mapping farmland: using area and trigonometry

In northern Queensland's Gulf region, some farmers use GPS mapping to help manage their extensive properties. Use this clip as a context for applying your understanding of area, in particular your understanding of conversion between square kilometres and hectares. Apply trigonometry and Pythagoras' theorem.

Interactive Resource

Area of a parallelogram

This is a Geogebra activity used to teach the area of a parallelogram. Suitable for use with an interactive whiteboard (IWB).

Interactive Resource

Numeracy wrap: Race across transversals

Interactive activities that guide students to explore angles in parallel lines.


BBC Bitesize: transformations - revision

This is a set of illustrated information sheets with a focus on congruence and transformations. Examples with answers are included and students have access to multiple-choice questions to assess their learning. This resource is one of a series of online resources from the BBC's Bitesize collection.

Teacher resource

TIMES Module 10: Measurement and Geometry: introduction to measurement - teacher guide

This is a 16-page guide for teachers. It provides an introduction to the initial ideas of measurement, and introduces the measurement of length, area, volume and time.