Monday, January 16, 2012

Squaring a Triangle

This applet shows the construction of a square with the same area as a given triangle.
This is a Java Applet created using GeoGebra from www.geogebra.org - it looks like you don't have Java installed, please go to www.java.com

Author: Irina Boyadzhiev of Ohio State University.

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Monday, January 9, 2012

Area of Triangles Under a Curve

Given: Right triangle BCD whose hypotenuse is tangent to the function f(x) = a/x

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)

  1. Move slider and observe what happens? How is the appearance of the graph relate to a?
  2. Move point A and observe the triangle? What do you observe?
  3. What conjecture can you make based on your observation in 2. Prove your conjecture. 

Thursday, January 5, 2012

Equation of a Circle

Move sliders h, k, and r to form the desired circle.

This is a Java Applet created using GeoGebra from www.geogebra.org - it looks like you don't have Java installed, please go to www.java.com

This applet shows that a circle can be determined given a center (h,k) and a radius r.


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Monday, January 2, 2012

Routh's Theorem

Move ABC to determine the shape of a desired triangle and move the slider. What do you observe?
This is a Java Applet created using GeoGebra from www.geogebra.org - it looks like you don't have Java installed, please go to www.java.com


The Routh's theorem determines the ratio of areas between a given triangle and a triangle formed by the intersection of three cevians. The theorem states that if in triangle ABC points DE, and F lie on segments BCCA, and AB, then writing \tfrac{CD}{BD}  x\tfrac{AE}{CE}  y, and \tfrac{BF}{AF}  z, the signed area of the triangle formed by the cevians ADBE, and CF is the area of triangle ABC times
\frac{(xyz - 1)^2}{(xy + y + 1)(yz + z + 1)(zx + x + 1)}.
This theorem was given by Edward John Routh on page 82 of his Treatise on Analytical Statics with Numerous Examples in 1896.


Source: Wikipedia


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