Circle O has a radius of 3 units. Points A and B are inside the circle such that AO=1 unit, BO=2 unit, and angle AOB=60 degrees.
CDE is an isosceles triangle inscribed in circle O with CD=DE, point A on CD and point B on DE.
How long are the sides of CDE?
DE and DC are each 5.92508 and EC is 1.86682 to the accuracy afforded by Geometer's Sketchpad.
Wolfram Alpha lists a possible closed form for the former as 2 pi  9/(8 pi) ~= 5.9250866852, and for the latter as e^(2/e  1) pi sin(e pi) ~= 1.866810407 or sqrt(70)/e^(3/2) ~= 1.866840857. An analytic solution would verify or preclude these surmises.
See the diagram:

Posted by Charlie
on 20190318 17:09:09 