It is impossible to trisect an angle using only ruler and compasses but it can be done using a carpenter's square.

Construct two equilateral triangles on a straight line. There are two lengths that look the same - can you prove it?

An equilateral triangle is constructed on BC. A line QD is drawn, where Q is the midpoint of AC. Prove that AB // QD.

ABCD is a square. P is the midpoint of AB and is joined to C. A line from D perpendicular to PC meets the line at the point Q. Prove AQ = AD.

Jennifer Piggott and Charlie Gilderdale describe a free interactive circular geoboard environment that can lead learners to pose mathematical questions.

Make five different quadrilaterals on a nine-point pegboard, without using the centre peg. Work out the angles in each quadrilateral you make. Now, what other relationships you can see?

Can you find triangles on a 9-point circle? Can you work out their angles?

Suggestions for worthwhile mathematical activity on the subject of angle measurement for all pupils.

Can you make a right-angled triangle on this peg-board by joining up three points round the edge?

Pythagoras of Samos was a Greek philosopher who lived from about 580 BC to about 500 BC. Find out about the important developments he made in mathematics, astronomy, and the theory of music.

Make an equilateral triangle by folding paper and use it to make patterns of your own.

Join pentagons together edge to edge. Will they form a ring?

Draw some angles inside a rectangle. What do you notice? Can you prove it?

Semi-regular tessellations combine two or more different regular polygons to fill the plane. Can you find all the semi-regular tessellations?

Can you find and prove the relationship between the area of a trapezium and the area of a triangle constructed within it?

What angle is needed for a ball to do a circuit of the billiard table and then pass through its original position?

What is the relationship between the angle at the centre and the angles at the circumference, for angles which stand on the same arc? Can you prove it?

Can you work out how these polygon pictures were drawn, and use that to figure out their angles?

Interior angles can help us to work out which polygons will tessellate. Can we use similar ideas to predict which polygons combine to create semi-regular solids?

Consider a watch face which has identical hands and identical marks for the hours. It is opposite to a mirror. When is the time as read direct and in the mirror exactly the same between 6 and 7?

You can use a clinometer to measure the height of tall things that you can't possibly reach to the top of, Make a clinometer and use it to help you estimate the heights of tall objects.

On a clock the three hands - the second, minute and hour hands - are on the same axis. How often in a 24 hour day will the second hand be parallel to either of the two other hands?

Explore patterns based on a rhombus. How can you enlarge the pattern - or explode it?

Shogi tiles can form interesting shapes and patterns... I wonder whether they fit together to make a ring?

My train left London between 6 a.m. and 7 a.m. and arrived in Paris between 9 a.m. and 10 a.m. At the start and end of the journey the hands on my watch were in exactly the same positions but the. . . .

Join the midpoints of a quadrilateral to get a new quadrilateral. What is special about it?

Never used GeoGebra before? This article for complete beginners will help you to get started with this free dynamic geometry software.

Can you use LOGO to create this star pattern made from squares. Only basic LOGO knowledge needed.

Have you ever noticed how mathematical ideas are often used in patterns that we see all around us? This article describes the life of Escher who was a passionate believer that maths and art can be. . . .

Can you use LOGO to create a systematic reproduction of a basic design? An introduction to variables in a familiar setting.

Have you ever wondered how maps are made? Or perhaps who first thought of the idea of designing maps? We're here to answer these questions for you.

The points P, Q, R and S are the midpoints of the edges of a non-convex quadrilateral.What do you notice about the quadrilateral PQRS and its area?

Where will the point stop after it has turned through 30 000 degrees? I took out my calculator and typed 30 000 ÷ 360. How did this help?

What shapes should Elly cut out to make a witch's hat? How can she make a taller hat?