Origami: Getting the Square Root of a Number

A rectangular piece of paper is folded in the middle, horizontally and vertically, to denote the rectangular coordinate axes. Another fold is made to denote y = - 1. Two points are constructed -- Point M on (0,1) and point P on (0,-n).

Fold the paper through P (by moving point P in the applet) such that point M is on y = -1 (by moving point Q in the applet).


Sorry, the GeoGebra Applet could not be started. Please make sure that Java 1.4.2 (or later) is installed and active in your browser (Click here to install Java now)


Problem: Prove that if point P is at (0,-n), then the intersection of the fold and the x-axis is at .

The discussion of the mathematics behind this applet and the ggb file will be available for download this week at Mathematics and Multimedia.