O: (0 | 0)
X = Point(Segment[(0 | 0), (20 | 0)])
B: X
breite(x) = 10 - x / 2
C: (x(X) | breite(x(X)))
D: (0 | breite(x(X)))
v1, a_{1}, b, a, d = Polygon(O, X, C, D)
u: a_{1} + (2 * b)
A: (a_{1} * b)
Text1: "u = " + u + ""
Text2: "A = " + A + ""
v2, f, g, h, i = Polygon((-1 | 0), (21 | 0), (21 | -1), (-1 | -1))