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Triangle Vertex Centroid and Missing Coordinate

Yes. Each axis averages three vertex coordinates. A missing coordinate equals three times the centroid coordinate minus the other two coordinates on that axis.

Formula & worked example
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How to use this calculator

Enter the known values in the units shown. Results update as you type.
Where results are editable, change one to solve backwards. Lock a value to hold it fixed.
Use the worked example to check the method. Reset restores the starting fields.

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Formula and method

Example in initial displayed units: x1 0, y1 0, x2 6, y2 0, x3 0, y3 3 gives Centroid x 2, Centroid y 1.

G = ((x₁+x₂+x₃)/3, (y₁+y₂+y₃)/3)

Worked example

Enter these known values and leave the other values blank.

x1: 0
y1: 0
x2: 6
y2: 0
x3: 0
y3: 3

Centroid x: 2
Centroid y: 1

Assumptions and limitations

Coordinates share one Cartesian scale. The result is the average of three vertex positions. For a nondegenerate triangle it is the geometric centroid; for collinear or coincident vertices it remains their coordinate average. Each coordinate equation supports its own inverse.
Use compatible units and enough independent values. Clear unknowns before solving backward. Original reference drawings are schematic and do not scale to entered values.

Common questions

Can I find a missing vertex coordinate from the centroid?