Straight lines can be drawn in any direction. Horizontal lines go left and right. Vertical lines go up and down. Parallel lines are a fixed distance apart and will never meet, no matter how long they ...

Find out about different regular and irregular polygons. What are the types of triangle? Find out about scalene, equilateral, isosceles and right-angled triangles. What are the parts of a circle?

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.