---
tag: 0C9MZY2RNA
kind: concept
name: Altitude of a triangle
aliases: [height-of-a-triangle]
msc: [51M04]
sources:
  - url: https://en.wikipedia.org/wiki/Altitude_(triangle)
    locator: lead section
same_as:
  wikidata: Q339495
  wikipedia: Altitude (triangle)
---

## Summary

An altitude of a triangle is the segment from a vertex to the line of the opposite side, at a right angle to that line. Its length, the height, is the distance from the vertex to that line.