David Little
Mathematics Department
Penn State University
Eberly College of Science
University Park, PA 16802
Office: 403 McAllister
Phone: (814) 865-3329
Fax: (814) 865-3735
e-mail:dlittle@psu.edu

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Simson's Theorem
Draw the projection of the yellow point onto each side of the triangle. Move the yellow point around to see what happens to the three projections. Can you determine when the three points are colinear?

Simson's Theorem states that the three points constructed above are colinear if and only if the yellow point lies on the circle determined by the vertices of the triangle. Draw the Circumscribed Circle through the vertices of the triangle and see for yourself. Can you prove Simson's Theorem?