Cynthia Lanius

Thanks to PBS for permission to use the Pyramid photo.

Circles around Pythagoras

If you need a definition


Three concentric circles have their centers at O, and OABC is a rectangle. Point C lies on the white circle, Point A lies on the pink circle, and Point B lies on the orange circle. The intersection point of the rectangle's diagonals lies on the pink circle.

  1. If the radius of the pink circle is 3, find:

    A. the area of the pink circle

    B. the area of the orange ring

  2. Can you find the area of the white ring?

    Yes No

    Please explain your answers.

    Name: Email Address:

  3. Pythagorean Links:

    PT and Its Many Proofs
    An Elementary Exploration
    An Animated Proof
    Animated Proof of the PT
    Another Proof by appletNova Online - Using the PT
    Nova Online - PT Puzzle

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