A tool by Leon Dudhill
Geometry Explorer 2D GCSE Maths
Drag vertices · Edit angles & sides · Interior & exterior angles always shown
Drag any vertex to reshape
Triangle selected Drag any vertex to change the shape
Drag vertices to reshape · Edit angles & side lengths in the right panel · Buttons show number of sides
Shape Properties
All values update live
Measurements
Perimeter
Area
Interior angle sum
Exterior angle sum 360°
Shape type
Angles
Side Lengths (units)
Interior sum = (n−2)×180° · Exterior angle = 360° − interior · Interior + Exterior = 360°
Disclaimer: Geometry Explorer 2D is a tool to help me study for my GCSE Maths. You are welcome to use it but it may have errors and shouldn't be relied on without independently fact checking answers.