When two lines intersect, the opposite (X) angles are equal. In the diagram above, the two green angles are equal and the two yellow angles are equal.

Here's the new description without the links: Learn how to define angle relationships. Knowledge of the relationships between angles can help in determining the value of a given angle. The various ...

Parallel lines are straight lines which have the same direction and so never meet. Arrowheads show lines are parallel. A straight line that cuts a pair of parallel lines is called an intersecting ...