Interactive resource
Converse of Pythagoras
Geometry. Use side lengths to decide whether a triangle is acute, right, or obtuse. Free interactive GeoGebra resource — adjust parameters in the browser.
Overview
Use side lengths to decide whether a triangle is acute, right, or obtuse.
Explanation
Converse: if sides a, b, c (c longest) satisfy a² + b² = c², the triangle is right-angled at the angle opposite c.
Test: a² + b² > c² → acute; a² + b² < c² → obtuse.
The theorem relates areas; the converse classifies the largest angle.
How to use
Adjust a, b, c and compare a² + b² with c² to read the largest angle type.