On this flat surface, triangles have exactly 180 degrees, and parallel lines go on forever and never intersect. This is called “Euclidean Geometry.” A fascinating branch of Geometry has developed ...

Why is this happening? Take a look at the two lines at the equator — they look parallel. However, in elliptic geometry there are no parallel lines because all lines eventually intersect.

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

Astronomers are very curious about the ultimate curvature of the universe: how do parallel lines and triangles behave on the very largest scales? They care because the shape of the universe is ...

Learn about and revise angles, lines and multi-sided shapes and their properties with GCSE Bitesize OCR Maths.