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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.

Bow Tie

Show how this pentagonal tile can be used to tile the plane and describe the transformations which map this pentagon to its images in the tiling.

Convex Polygons

Show that among the interior angles of a convex polygon there cannot be more than three acute angles.

Getting an Angle

Age 11 to 14
Challenge Level

Remember that folding an equilateral triangle in half gives you a 30-60-90 triangle and the ratios of the lengths of the sides.