X(x|f(x))

O: (0, 0)
breite(x) = 10 - x / 2
B_{1}: (8, 0)
B: (8, 6)
A: (0, 10)
v1, o, b, c, d = Polygon(O, B_{1}, B, A)
X = Point(Segment[B, A])
E: (x(X), 0)
F: (0, y(X))
R, o_1, e, x_1, f = Polygon(O, E, X, F)