Parallel lines in shapes can form corresponding and alternate angles. You can use these properties to find missing angles. Part of Maths Angle, symmetry and transformation ...

Learn about and revise angles, lines and multi-sided shapes and their properties with this BBC Bitesize GCSE Maths Edexcel study guide.

If you have forgotten your basic geometry, parallel lines are represented by the little squares you see above, which signify 90-degree angles. Here’s the catch, non-Euclidean geometry does not ...

• Lines which are parallel to a given line are parallel to each other. • The sum of the three angles of a triangle is 180°. • If a side of a triangle is produced, the exterior angle so ...