Mathematics / Year 8 / Measurement and Geometry / Geometric reasoning

• TLF-IDM025320

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 ...

• TLF-IDM016790

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 ...

• TLF-IDM021845

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 ...

• TLF-IDM024946

Are triangles really the strongest shapes ever? If so, why? Learn how and why right-angled and equilateral triangles have been used in engineering, architecture and design through the ages.

• TLF-IDM017685

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.

• TLF-IDM008817

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.

• TLF-IDM008822

This is a 16-page guide for teachers. It provides an introduction to the initial ideas of plane geometry. Points and lines are introduced as fundamental objects in the study of geometry. Angles and parallelism are the initial areas of attention in a more formal approach to geometry that occurs from year 7.

• TLF-IDM012845

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 ...

• TLF-IDM008601

This is a 15-page guide for teachers containing explanations of the derivation of formulas for the areas of parallelograms, trapeziums, rhombuses and kites. Formulas for the volumes and surface areas of prisms and cylinders are obtained. Applications of these formulas are given. A history of the development of these concepts ...

• TLF-IDM015626

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.