Free · Algebra and geometric relations

Triangle Perimeter from Vertex Coordinates

Measure the three Euclidean sides and their sum from planar coordinates.

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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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For the worked example, Side AB = 3, Side AC = 4, Side BC = 5, Perimeter = 12.

AB=√((xB−xA)²+(yB−yA)²); P=AB+BC+CA

Enter these known values and leave the other values blank.

All coordinates use the same scale. Vertices must be distinct and noncollinear.
Coordinate inverses retain one positive square-root branch; forward distance does not depend on vertex order.

Choose the relevant mode and enter independent known quantities. Leave a missing value empty where the control permits an inverse.

The result follows the stated mathematical model. All dimensions must use consistent units; available unit selectors handle conversions.

Bookify validates the real geometric or algebraic domain and inverse branches omitted or approximated by this capture.