JSP-Applet: Theorem of Pythagoras

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Sketch

The sketch below shows a right triangle with squares constructed on its three sides. You can drag vertex A to change the size and shape, but it will remain a right triangle.

 

Applet 1 starten

 

Investigate

  1. Click "Construct Center of Square" to show center O of the square on the longer leg. The center of a square is located at the intersection of the diagonals.
  2. Click "Construct j and k" to show two lines through O: line j perpendicular to the hypotenuse and line k perpendicular to line j. Lines j and k divide the square on the longer leg into four quadrilaterals. Click "Construct Quadrilaterals" to show the quadrilaterals and the square on the shorter leg.
  3. Click "Hide Construction Lines." Now move the green quadrilaterals in the square on leg b into the square on the hypotenuse by dragging points P and P'.
  4. Move the yellow quadrilaterals in the square on leg b into the square on the hypotenuse by dragging points Q and Q'.
  5. Move the pink square in the square on leg a into the square on the hypotenuse by dragging point R.
  6. Formulate the Pythagorean Theorem: In a right triangle, the sum of the squares of the lengths of the legs equals the square of the length of the hypotenuse. If a and b are the lengths of the legs, and c is the length of the hypotenuse, then _____.

Sketch

Use this sketch to investigate whether or not the Pythagorean Theorem works for all triangles. The triangle in the sketch is not a right triangle and you can drag any of the vertices to change the triangle. Click the button if you want to make it into a right triangle.

 

Applet 2 starten

 

Investigate

  1. When is a2 + b2 equal to c2?
  2. When is a2 + b2 greater than c2?
  3. When is a2 + b2 less than c2?

This is a prototype of JavaSketchpad, a World-Wide-Web component of The Geometer's Sketchpad. Copyright & copy ; 1990-1998 by Key Curriculum Press, Inc. All rights reserved. Portions of this work were funded by the National Science Foundation (awards DMI 9561674 & 9623018).

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