A geometric theorem related to the Pentagram and also called the Pratt-Kasapi Theorem.

In general, it is also true that

This type of identity was generalized to other figures in the plane and their duals by Pinkernell (1996).

**References**

Chou, S. C. *Mechanical Geometry Theorem Proving.* Dordrecht, Netherlands: Reidel, 1987.

Grünbaum, B. and Shepard, G. C. ``Ceva, Menelaus, and the Area Principle.'' *Math. Mag.* **68**, 254-268,
1995.

Hoehn, L. ``A Menelaus-Type Theorem for the Pentagram.'' *Math. Mag.* **68**, 254-268, 1995.

Pinkernell, G. M. ``Identities on Point-Line Figures in the Euclidean Plane.'' *Math. Mag.* **69**, 377-383, 1996.

© 1996-9

1999-05-25