What is the sum of the angles of a triangle whose sides are circular arcs on a flat surface? What if the triangle is on the surface of a sphere?
Six circles around a central circle make a flower. Watch the flower as you change the radii in this circle packing. Prove that with the given ratios of the radii the petals touch and fit perfectly.
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?
Construct this design using only compasses
A spiropath is a sequence of connected line segments end to end taking different directions. The same spiropath is iterated. When does it cycle and when does it go on indefinitely?
P is a point inside a square ABCD such that PA= 1, PB = 2 and PC = 3. How big is angle APB ?
Can you use LOGO to create this star pattern made from squares. Only basic LOGO knowledge needed.
Why does this fold create an angle of sixty degrees?
What angle is needed for a ball to do a circuit of the billiard table and then pass through its original position?
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.
Explore patterns based on a rhombus. How can you enlarge the pattern - or explode it?
Jennifer Piggott and Charlie Gilderdale describe a free interactive circular geoboard environment that can lead learners to pose mathematical questions.
Join some regular octahedra, face touching face and one vertex of each meeting at a point. How many octahedra can you fit around this point?
Use simple trigonometry to calculate the distance along the flight path from London to Sydney.
An equilateral triangle is constructed on BC. A line QD is drawn, where Q is the midpoint of AC. Prove that AB // QD.
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?
Join the midpoints of a quadrilateral to get a new quadrilateral. What is special about it?
Suggestions for worthwhile mathematical activity on the subject of angle measurement for all pupils.
What shapes should Elly cut out to make a witch's hat? How can she make a taller hat?
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?
Semi-regular tessellations combine two or more different regular polygons to fill the plane. Can you find all the semi-regular tessellations?
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?
Can you use LOGO to create a systematic reproduction of a basic design? An introduction to variables in a familiar setting.
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. . . .
How did the the rotation robot make these patterns?
A quadrilateral changes shape with the edge lengths constant. Show the scalar product of the diagonals is constant. If the diagonals are perpendicular in one position are they always perpendicular?