Obtuse angle – GeoGebra

Exploring Types of Angles – GeoGebra

Module 1 (M1) - Geometry & measures - properties of angles - BBC Bitesize

Obtuse Angle Test – GeoGebra

Obtuse Angles – GeoGebra

Construction of Scalene Triangle in GeoGebra

Is 9.6in, 20.1in, and 18in an acute, obtuse, or a right angle? - Quora

Dynamic visual proofs using DGS - Document - Gale Academic OneFile

exzuberant: Really, really understanding the area of a triangle (Part 2)

Reflex, obtuse and acute animation – GeoGebra