When two lines cross, there are four angles at the place where they cross. Two angles that do NOT share a side are vertical angles. There are two pairs of vertical angles where the lines cross.
Also, by the way, vertical angles are always equal to each other. It's often very helpful to know that.
When two angles of two lines are directly facing one another, or opposite, hope this helps!
Vertically opposite angles are formed by the intersection of two lines, creating pairs of equal angles that do not share a side. When two lines cross, the angles opposite each other are congruent, meaning they have the same measure. For example, if one angle is 50 degrees, the angle directly opposite is also 50 degrees.
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