What is a transversal in geometry?

A transversal in geometry is defined as a line that intersects two or more other lines in a plane. This definition is crucial because the properties and relationships that arise from this intersection are fundamental to various geometric theorems and concepts, especially in the context of parallel lines and angles.

When a transversal crosses two parallel lines, it creates several pairs of angles—corresponding angles, alternate interior angles, and same-side interior angles—that have specific relationships that can help in solving problems related to angles and lines. Understanding how a transversal interacts with these lines is essential for exploring concepts such as angle relationships and proving geometric theorems.

The other options do not accurately describe a transversal. The first option incorrectly limits the intersection to one line, while the third suggests a specific orientation (perpendicular) that does not encompass all cases of transversals. Lastly, describing a transversal as a horizontal line ignores that a transversal can have any orientation as long as it intersects multiple lines. Thus, the correct definition acknowledges the broader application of transversals in geometry.