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

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רישום חופשי
גיליון אלקטרוני להעלאת נתוני בעיה ויצירת גרף בהתאם
Perpetual calendar
Construcing a 60° Angle and Properties of 30°-60°-90° Triangles
Subdivision of a polynomial into triangles.

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Descobrindo relações entre ângulos
Integrating Evenly Even Powers of the Sine Function
Activity 6 Reflection Trapezoid
Mappin #4
GeoGebra 3D Beginner Tutorial: Exercise 1

Discover Topics

Angles
Complex Numbers
Integral Calculus
Polynomial Functions
Parabola