Els triangles BFE i BDC haurien de tenir els costats 

proporcionals

A = (11, -2)
B = (1, -2)
C = Rotate(A, 35°, B)
α = Angle(A, B, C)
a = Segment(B, A)
b = OrthogonalLine(C, a)
c = Segment(B, C)
D = Intersect(b, a)
E = Point(c)
d = Line(E, b)
F = Intersect(d, a)