Euclidean geometry is the kind you were taught at school, the world of sines and cosines, and the square on the hypotenuse ...

Parallel lines close parallel lines Lines which never meet and stay the same distance apart. Parallel lines are indicated by a pair of arrows. are two or more straight lines that remain the same ...

Horizontal lines run left to right, parallel to the horizon, with slope 0 and equation y = k. Vertical lines run top to bottom, perpendicular to the horizon, with undefined slope and equation x = k.

Roula Khalaf, Editor of the FT, selects her favourite stories in this weekly newsletter. Therapist Martin Carr is in a quandary. He has learnt that a new patient, Carmen, is already known to his ...