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2x2xKit

Triangle Calculator

Calculate a triangle's area, perimeter and angles from its three sides.

How this is calculated
Heron's formula for area; law of cosines for angles

Assumptions used in this calculation

  • Valid triangle: Assumes the three side lengths satisfy the triangle inequality; inputs that can't form a triangle are rejected.

About this calculator

Solves a triangle from its three side lengths using Heron's formula (area) and the law of cosines (angles), and classifies it by side and angle type, consolidating the master prompt's separate 'Right Triangle Calculator', since this classification identifies right triangles directly.

Worked example

3-4-5 triangle

Result: Area = 6, right triangle

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