Angle-area graph for an irregular quadrilateral

We show the possible shapes and areas of a quadrilateral with sides a,b,c,d (clockwise) as angles are changed.

Side-lengths are specified at the beginning.

No side can be larger than the sum of the others.

Points B and C can be dragged to change the shape. In the second board A is angle alpha.

(Labels can also be dragged if they get in the way).

Last change July 2023.

All graphics created with JSXgraph.

Made in Mexico, National Autonomous University of Mexico ( UNAM ), all rights reserved 2015.
This page may be reproduced for non-commercial purposes as long as it is cited, not mutilated and its address is given.
Otherwise, written permission from the institution is required in advance.
The information and programs are provided "as is", with no warranty whatsoever, implicit or explicit.
Copyright © 2016