Aire du parallélogramme

Aire=b\times h

B = (2, 4)
C = (2, 7)
D = (5, 7)
E = (6, 4)
Q, c_1, d, b, h = Polygon(C, D, E, B)
α = 0 (slider from 0 to 4, step 0.1)
A: (1 + α, 7)
F: (2 + α, 7)
G: (2 + α, 4)
P, g, a, f = Polygon(A, F, G)