A = (0, 0)
B = Point(xAxis)
C = (5, 3)
a = 1.26 (slider from 0 to 3, step 0.01)
M: (a, 0.0)
N: (5.0, a)
P: (0.0, 3.0 - a)
b = Segment(A, B)
c = Segment(B, C)
poly1, p, m, n = Polygon(M, N, P)
L: (a, poly1)