Area of a Parallelogram

Drag the blue point at the bottom left.

A = b \, h

Area of a parallelogram

A = (0, 0)
B = (0, 2)
C = (5, 2)
D = (4, 0)
E = (-1, 0)
a = Segment(E, D)
b_1 = Segment(D, C)
b = Segment(C, B)
d = Segment(B, A)
F = Point(a)
G = Point(Circle[F, 1])
e = Segment(F, G)
f = OrthogonalLine(G, a)
H = Intersect(b, f)
g = Segment(H, F)
h = Segment(H, G)
I = Point(d)
i = Segment(D, I)