What do you notice? Why does this happen? Will it […]
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 […]
This diagram shows a proof.
Look carefully. Can you see three squares?
Assuming that they are squares, can you prove that four of the triangles are congruent?
Can you now write down a proof of Pythagoras’ Theorem and explain the proof?
The second diagram […]
This shape is an equilateral triangle sitting on top of a square.
What is the radius of the circle that circumscribes the shape?
Click here for a hint if you need one to get started.
This problem is adapted from the […]
The diagram shows three angles a, b and c.
How many ways can you prove that a + b = c?
What other interesting properties can you find?
When this activity was originally published on NRICH, two boys from Madras School in St Andrew’s, Scotland sent […]