Quadrilateral Surprise!

Author:Tim Brzezinski

How would you put this property (dynamically illustrated below) into words? (Applet works best if quadrilateral is kept convex.) How can you formally prove what this applet informally illustrates?

Quick (Silent) Demo

New Resources

Let's fly!
bewijs stelling van Pythagoras
Monge's Theorem
רישום חופשי
Pendulum Snake

Discover Resources

Introduction to Concept of Locus
Thales' Theorem Quiz
Rotations Exploration 1 - 90° (Student Copy)
สมการเชิงเส้น

Discover Topics

Parabola
Angles
Unit Circle
Perimeter
Exponent