For example, let's say six adjacent angles add up to 360 degrees making them vertical angles, and they can be sorted into three pairs of opposite angles. Two values are known, and four are unknown.

Horizontal and vertical angles are often not the same. For example, looking down on a screen may have less of a viewing angle than from the side and more of a viewing angle than from the bottom.

We see lines everywhere around us all the time, for example on buildings, books, televisions, photo frames, roads etc. Did you know that different types of lines have different names? A vertical ...