Illustrated · 1 min
Transversals are like bridges between two lines
Angles are created when lines intersect, and their measure is determined by how they intersect. When two lines are parallel, any line that intersects with one of them will intersect with the other in exactly the same way. The lines that cross through two lines, parallel or not, are called transversals.
When the lines are parallel
In the image above, line EF is a transversal across parallel lines AB and CD. The angles around point Y and point Z are identical to each other.
When angles are in the same place relative to the intersection (FZD and ZYB, for example), they're called corresponding angles. Corresponding angles are always congruent.
When angles would be on either side of a vertex if they were in the same set (for example, FZD and EYA), they're called alternate angles. Alternate angles are always congruent.
When angles would be next to each other if they were in the same set (for example, FZD and BYE), they're called consecutive angles. Consecutive angles are rarely congruent, but they're always supplementary.