**"Properties of 2D shapes"**

## Years 10 – 11: Investigating circle theorems

*By Barrie Barnard On 27 August, 2020 · Leave a Comment*

Activity 1: Finding the centre of the circle

You will need a cut-out paper circle (about 12cm diameter).

Use a circle that does not show the centre. Fold your circle along a diameter. Mark the ends A and B. Now unfold your circle and then fold again along a different diameter and mark the […]

## Years 5 – 9 Tangram Fractions

*By toni On 14 August, 2020 · 4 Comments*

This is a classic Chinese Tangram. Each of the people illustrated, and many convex polygons, can be made with the 7 pieces and there are hundreds of other puzzles based on this tangram.

Can you find a way to fold a sheet of paper so that you can cut out the tangram pieces accurately […]

## Years 4 – 7 Tangram Pattern

*By toni On 11 August, 2020 · Leave a Comment*

Arrange the 7 tangram pieces to make the shape in the grey picture.

What do you notice about this shape?

Describe the shapes of the tangram pieces.

What is the same and what is different about the shapes of the tangram pieces?

Make a pattern of your own using all 7 pieces.

[…]

## Years 6-10 Collapsible Cube

*By toni On 11 June, 2020 · Leave a Comment*

Make a 3D cube out of rolled paper sticks, tied together at the ends. Push your cube gently down and sideways. It will collapse into a 2D shape. Can you collapse your cube into

a 2D rectangle made of 2 squares?

Can you fold […]

## Years 7 – 9 Tangram 2D Shapes

*By Elizabeth Turok On 30 May, 2020 · Leave a Comment*

To make your 7-piece Tangram Puzzle, either make your own tangram pieces from scrap paper as shown in this video or use this diagram and carefully cut out the pieces.

Now use the pieces of your Tangram to make

• An isosceles triangle

• A rectangle

• A […]

## Years 8 – 12 Pythagoras Jigsaw

*By toni On 23 May, 2020 · Leave a Comment*

The right angled triangles numbered 1, 2, 3 and 4 in the diagrams all have sides of length a, b and c. They are identical (congruent) copies of each other.

Cut 4 congruent right angled triangles from some scrap paper. Arrange them as shown in diagram […]

Look at this square divided into four pieces : two identical triangles and two identical trapezia.

The edge of length 3 from each triangle matches with the edge of length 3 from a trapezium so that the four pieces from the square now occupy a rectangular space.

The square had side length 8 […]

## Years 8 – 12 Tri-Fold

*By toni On 15 May, 2020 · Leave a Comment*

Take any triangle and label it ABC with A as the largest angle. Fold the triangle along PQ, PS and QT where the points P and Q are the midpoints of AB and AC and PS and PT are perpendicular to BC.

What do you notice? Why does this happen? Will it […]

## Years 8 – 11 Triangles to Tetrahedra

*By toni On 15 May, 2020 · Leave a Comment*

A tetrahedron (plural tetrahedra) is a solid with four triangular faces. How many different tetrahedra can you make using the four different types of triangle shown in the diagram if you have an unlimited number of each type?

Type R are right angled isosceles triangles with sides a, a and b units.

Type […]

## Years 6 – 8 Properties of parallelograms

*By Barrie Barnard On 8 May, 2020 · Leave a Comment*

We start from this definition:

A parallelogram is a quadrilateral with both pairs of opposite edges parallel.

In this investigation you will discover some other properties of parallelograms.

Step 1: Use two different width rulers to draw a parallelogram on tracing or baking paper.

Make sure that it is […]

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