Euler Line Calculator

Understanding the Euler Line

What is the Euler Line?

The Euler line is a remarkable straight line that contains several important points of a triangle:

  • Orthocenter (H)
  • Centroid (G)
  • Circumcenter (O)
  • Nine-point center (N)

These points always lie on the same line, except in equilateral triangles where they coincide.

Key Properties

  • HG:GO = 2:1
  • N is midpoint of HO
  • G divides HO in ratio 2:1
  • Exists in all triangles
  • Parallel to longest side in obtuse triangles

Triangle Centers

Orthocenter (H)

Intersection of altitudes

Centroid (G)

Intersection of medians

Circumcenter (O)

Center of circumscribed circle

Nine-point center (N)

Center of nine-point circle

Special Cases

Triangle Type Euler Line Property
Equilateral All centers coincide
Right H at right angle vertex
Obtuse H outside triangle
Acute H inside triangle

Advanced Properties

Distance Relationships

  • OH = 3R cos A cos B cos C
  • ON = R/2
  • HN = 2R cos A cos B cos C

Circle Properties

  • Nine-point circle radius = R/2
  • Euler circle contains feet of altitudes
  • Contains midpoints of sides

Applications and Extensions

Geometry

Triangle center relationships

Engineering

Structural analysis

Physics

Center of mass calculations

Architecture

Design and symmetry