# Category Archives: Geometry

## 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… Read More »

## If One World Trade Center is a prism and not an antiprism, would it be less in volume?

One World Trade Center, more simply known as 1 WTC and previously known as the Freedom Tower, is the lead building of the new World Trade Center complex in Lower Manhattan, New York City. The supertall skyscraper is 104 storey  and is being constructed in the northwest corner of the 16-acre World Trade Center site. The image at the right shows the design as… Read More »

## Regular Polygons Problems

One of my favourite lesson design is a sequence of problem solving tasks that requires repetition of same reasoning and analysis by varying the ‘mathematical context’ of the problem in increasing complexity. However the variation in the context of the problem should be such that they still share some properties. In the examples below, the… Read More »

## The Pythagorean Theorem Puzzle

Math puzzles are great activities for enjoying and learning mathematics. The following is an example of Tachiawase. Tachiawase is a popular puzzle in Japan which involve dissecting a geometrical figure into several parts and then recombining them to form another geometrical figure. The puzzle below is credited to Hikodate Nakane (1743). This was one of… Read More »