Mathematics for Teaching Category: Geometry

Category: Geometry

Convert a Boring Geometry Problem to Exploratory Version

The following problem (or proving activity, if you like to call it that) is a typical textbook geometry problem. It is tough and guaranteed to scare the wits out of any Year 9 student. When I used the given condition to construct the figure using GeoGebra, the only thing I can move is A or…

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Unpacking mathematics – a geometry example

Engineers, mathematicians, and mathematics teachers all deal with mathematics but it is only the math teacher who talks about math to non-mathspeakers and initiate them to ‘mathspeak’. To do this, the math teachers should be able to ‘unpack’ for the students the mathematics that mathematicians for years have been so busy ‘packing’ (generalising and abstracting)…

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A Geometric Model for the Lunch Date Problem

A mathematical model is an abstract model that uses mathematical language to describe and understand a situation. Here’s a nice video that presents a model for the Lunch Date Problem. The video below shows a step-by-step tutorial using SketchPad to build a geometric model of the problem. What is nice about this video is that it…

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Pentagon to Quadrilateral Puzzle

Puzzles involving cutting shapes and forming them into different shapes helps reinforce the idea that area do not necessarily change with change in shape. It is also a good activity for developing visualisation skill and spatial ability. The puzzle below is from one of the leaflets at the booth of Japan Society of Mathematical Education last ICME…

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A problem solving lesson about triangles and circles

This short lesson was inspired by one of the problems from the blog Five Triangles Mathematics. The author challenges the reader to construct a circle using only a compass and straight edge, through two points X and Y. The centre of the circle must be a point on the line located between the two given…

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