A static sketch can’t answer “if I move the point, does it still hold?” Drag the point in class and students see what changes and what doesn’t.
Visualization is built for that kind of check: does the relation survive, where’s the invariant?
Good demo topics
- Pythagoras: how areas track when side lengths change
- Inscribed vs central angles
- Corresponding sides in similar triangles
- Corresponding / alternate interior angles with a transversal
Short arc
- State a conjecture
- Drag to test
- Write the relation or theorem line in the formula editor
Visualization for intuition, formulas for exam language. Clear split—no need to force both into one window.