Brahmagupta's theorem

${\displaystyle {\overline {BD}}\perp {\overline {AC}},{\overline {EF}}\perp {\overline {BC}}}$ ${\displaystyle \Rightarrow |{\overline {AF}}|=|{\overline {FD}}|}$

The Brahmagupta theorem is a statement in Euclidean geometry on track conditions in certain tendons squares.

"If the diagonals are perpendicular to each other in a chordal quadrilateral , then the perpendicular divides the opposite side into 2 equal sections through the diagonal intersection on one side."

The statement is named after the Indian mathematician and astronomer Brahmagupta (598–668).

literature

• HSM Coxeter , SL Greitzer: Timeless geometry . Klett, Stuttgart, 1983

Web links

• Eric W. Weisstein : Brahmagupta's theorem . In: MathWorld (English).
• Brahmagupta's sentence at cut-the-knot