The Two Triangles Theorem

Let the points P, Q, and R lie on a parabola. Let P', Q', and R' be the intersection points of the tangents to the parabola at Q and R, P and R, and P and Q, respectively. The area of triangle PQR (purple) is twice the area of triangle P'Q'R' (gold). Drag the black points to change the figure.

The theorem and the idea for the image are from:
L. W. Cusick, "Archimedean Quadrature Redux," Mathematics Magazine, 81(2), 2008 p. 83.
comments
 
Powered by Wolfram Mathematica
Give us your feedback
Give us your feedback

Source page:




 often  occasionally  never

Note: Please do not include anything you consider confidential or proprietary. Your message and contact information may be shared with the author of any specific Demonstration for which you give feedback, but will not otherwise be published or distributed.
Privacy Policy »

Note: To run this Demonstration you need the free
Mathematica Player
or Mathematica 7+
Download or upgrade to Mathematica Player 7
I already have Mathematica Player or Mathematica 7+