Yes, of course, Pythagoras theorem :) In fact, if our quadrilateral is a rectangle… then opposite sides are the same length, and the diagonals are also of the same length… and so Ptolemy’s theorem ...
https://doi.org/10.4169/college.math.j.43.5.386 https://www.jstor.org/stable/10.4169/college.math.j.43.5.386 Building on two centuries' experience, Taylor & Francis ...
The Mathematical Gazette, Vol. 11, No. 162 (Jan., 1923), pp. 236-237 (2 pages) ...
To find E within ΔABC such that AE sin BEC + BE sin CEA + CE sin AEB shall be a maximum.
Some results have been hidden because they may be inaccessible to you
Show inaccessible results