Parallel lines are lines that never cross each other - they keep the same distance apart from each other. When two lines intersect, the opposite (X) angles are equal. On parallel lines ...

When a pair of parallel lines meet an intersecting transversal, pairs of angles with particular properties are made. Corresponding angles are equal. The lines make an F shape. Notice that the F ...

An easy way to remember congruent angles is to relate the word "congruent" and to how that term is used in reference to parallel lines: Two parallel lines with the same measure are congruent.