There it is possible for triangles to have something other than 180 degrees and for parallel lines, such as the longitudinal lines on the globe, to eventually intersect. Imagine the parallel sides of ...

This KS2 maths article explains how parallel lines are always the same distance apart and never meet. A perpendicular line is at right angles to another line.

Learn how to find equations of parallel lines, work out the gradient of perpendicular lines, and prove that given lines are parallel or perpendicular.