Question 1101490
To label use locate as Edwin did in the next problem.
(Trigonometry-basics/1101510:)
locate(0,0,B),locate(5,0,C), locate(.6,2.8,A)
locate(.1,1.2,c),locate(2.5,1.7,b=5m), locate(2,0,a=5m)
The first two entries are the x, y and the third entry is your label