perpendicular

perpendicular

The word "perpendicular" has a few closely related meanings, primarily in geometry and everyday language.

Core Meaning

It describes a relationship where two lines, surfaces, or objects meet at a right angle (90°).

1. In Geometry & Mathematics

This is the most precise and common usage.

Perpendicular Lines: Two lines that intersect at a 90° angle.

Symbol: Often denoted by ⟂. For example, line AB ⟂ line CD.

Key property: The slopes of two perpendicular lines (in a Cartesian plane) are negative reciprocals of each other (e.g., 2 and -1/2).

Perpendicular Bisector: A line that cuts another line segment into two equal parts at a right angle.

Perpendicular to a Plane/Curve: A line is perpendicular to a plane if it is perpendicular to every line in that plane that passes through its intersection point.