Angles - points, lines and parallel lines

problem
Isosceles seven

Age

14 to 16

Challenge level

Is it possible to find the angles in this rather special isosceles triangle?
problem
Triangle in a trapezium

Age

11 to 16

Challenge level

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

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

Age

11 to 14

Challenge level

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

Age

7 to 11

Challenge level

This task looks at the different turns involved in different Olympic sports as a way of exploring the mathematics of turns and angles.
problem
National flags

Age

7 to 11

Challenge level

This problem explores the shapes and symmetries in some national flags.
problem
Cylinder cutting

Age

7 to 11

Challenge level

An activity for high-attaining learners which involves making a new cylinder from a cardboard tube.
problem
Which solids can we make?

Age

11 to 14

Challenge level

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?
problem
Outside the nonagon

Age

11 to 14

Challenge level

Weekly Problem 44 - 2010
Extend two of the sides of a nonagon to form an angle. How large is this acute angle?
problem
Angle hunt

Age

11 to 14

Challenge level

Weekly Problem 39 - 2010
If you know three lengths and an angle in this diagram, can you find another angle by calculation?