Mathematics / Year 9 / Measurement and Geometry / Geometric reasoning

• TLF-IDM021841

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 ...

• TLF-IDM013359

This is a website designed for both teachers and students, which addresses similarity from the Australian Curriculum for year 9 students. It contains material on enlargement transformation and similar triangles. There are pages for both teachers and students. The student pages contain interactive questions for students ...

• TLF-IDA003201

This planning resource for Year 9 is for the topic of Algorithms. Students draw upon their knowledge of congruency, transformations and ratios of right-angled triangles and apply creativity, critical thinking and reasoning skills to a sequenced geometric problem. For example, students may design a flow chart to prove the ...

• TLF-IDM009038

This is a 19-page guide for teachers. It introduces quadratic equations and methods for solving them.

• TLF-IDM008608

This is a 20-page guide for teachers containing an introduction to the three basic trigonometric ratios. A history of trigonometry concludes the module.

• TLF-IDM013358

This is a website designed for both teachers and students, which addresses the surface area and volume of prisms and cylinders from the Australian Curriculum for year 9 students. It contains material on calculating the surface area and volume of prisms and cylinders. There are pages for both teachers and students. The student ...

• 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-IDM025325

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 ...

• TLF-IDM025321

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 ...

• TLF-IDM025324

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 ...