Perpendicular 和 vertical 这两个词经常出现在数学、物理课本里，它们都有“垂直的、成直角的”意思。它们之间的区别是什么呢？其实很简单，perpendicular 通常后面搭配介词 to，表示与某一物体构成直角。但这并不代表 perpendicular 就一定是“垂直竖立的”。Vertical ...

Why not see how much you know about this topic already? Then work through the page and see if you can beat your score. Parallel lines are the same distance apart from each other all the way along ...

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.

Whether you are sketching graphs in mathematics, understanding directions in geography, or reading blueprints in design class, horizontal and vertical lines are concepts you cannot avoid. They form ...