Circumcenter Calculator

Calculate the circumcenter and circumradius of a triangle from vertex coordinates

Triangle Vertices

First vertex (x₁, y₁)

Second vertex (x₂, y₂)

Third vertex (x₃, y₃)

Circumcenter Results

Invalid Triangle
The points are collinear or identical

Step-by-Step Solution

1.The points are collinear and do not form a valid triangle.

Example Calculation

Right Triangle Example

Problem: Find the circumcenter of triangle with vertices at A(0,0), B(3,0), and C(0,4).

Note: This is a right triangle with the right angle at vertex A.

Solution

Given: A(0,0), B(3,0), C(0,4)

Calculate J: (0-3)(0-4) - (0-0)(0-0) = 12

Calculate t: 0² + 0² - 3² - 0² = -9

Calculate u: 0² + 0² - 0² - 4² = -16

Circumcenter X: -((0-0)(-16) + (0-4)(-9)) / (2×12) = 1.5

Circumcenter Y: ((0-3)(-16) - (0-0)(-9)) / (2×12) = 2

Result: Circumcenter at (1.5, 2), which is the midpoint of hypotenuse BC.

Circumcenter Formula

Given vertices:

A(x₁,y₁), B(x₂,y₂), C(x₃,y₃)

Calculate:

J = (x₁-x₂)(y₁-y₃) - (x₁-x₃)(y₁-y₂)
t = x₁² + y₁² - x₂² - y₂²
u = x₁² + y₁² - x₃² - y₃²

Circumcenter:

x = -(y₁-y₂)u + (y₁-y₃)t / (2J)
y = (x₁-x₂)u - (x₁-x₃)t / (2J)

Circumcenter Location

Acute Triangle: Circumcenter lies inside the triangle
Right Triangle: Circumcenter is at the midpoint of the hypotenuse
Obtuse Triangle: Circumcenter lies outside the triangle
Equilateral Triangle: Circumcenter coincides with centroid and orthocenter

Understanding the Circumcenter

What is a Circumcenter?

The circumcenter of a triangle is the center of the circumscribed circle (circumcircle) - the unique circle that passes through all three vertices of the triangle. It's the point where the perpendicular bisectors of the triangle's sides intersect.

Key Properties

  • Equidistant from all three vertices
  • Center of the triangle's circumcircle
  • Location depends on triangle type
  • Every triangle has exactly one circumcenter

Mathematical Derivation

The circumcenter formula is derived from the condition that it must be equidistant from all three vertices. Using the distance formula and solving the system of equations D₁ = D₂ = D₃ leads to the coordinate formulas.

Applications

  • Geometric constructions and proofs
  • Computer graphics and CAD systems
  • Navigation and GPS triangulation
  • Engineering and architectural design

Fun Fact: The circumcenter, centroid, and orthocenter of any triangle are collinear and lie on the Euler line!