You may also like

problem icon


A floor is covered by a tessellation of equilateral triangles, each having three equal arcs inside it. What proportion of the area of the tessellation is shaded?

problem icon

Getting an Angle

How can you make an angle of 60 degrees by folding a sheet of paper twice?

problem icon

Arclets Explained

This article gives an wonderful insight into students working on the Arclets problem that first appeared in the Sept 2002 edition of the NRICH website.

Star Polygons

Age 11 to 14 Challenge Level:
If you know the five interior angles of the pentagon, what other angles can you work out?
What do you know about the angle sum of a pentagon?
Could algebra help?