| |
| | Menelaus and Ceva |
 | | To illustrate, consider three points A,B,C on the Euclidean plane, and let a,b,c denote points on the opposite edges of the triangle formed by those points. The general projective coordinates of the basis vectors A, B, and C are (k |
 | | Thus Ceva's condition is sufficient as well as necessary to ensure that a,b,g are valid barycentric coordinates of a single point, so the proof is complete. Incidentally, making use of the third equality for each coefficient, we can reduce the expressions for these coordinates to |
 | | For the same set of velocities, the Theorem of Ceva gives six lines that intersect in four points, one internal and three external, as shown below. |
| www.mathpages.com /home/kmath442/kmath442.htm (922 words) |
|