# Perpendicular

From Encyclopedia of Mathematics

*to a given straight line (plane)*

A straight line intersecting that straight line (plane) at right angles.

#### Comments

Two lines intersecting at right angles are also said to be orthogonal or perpendicular (cf. also Perpendicular straight lines).

**How to Cite This Entry:**

Perpendicular.

*Encyclopedia of Mathematics.*URL: http://encyclopediaofmath.org/index.php?title=Perpendicular&oldid=14970