# Orthocentre of a Triangle

Interact with the applet for a few minutes.
The

**purple lines**are the**ALTITUDES**of the triangle. The**blue point**is the**ORTHOCENTRE**of the triangle.## What is an orthocentre?

*An orthocentre of a triangle is ...*

## Investigate the orthocentre of a triangle

Move the vertices of the triangle around. What happens with the orthocentre?