Move any vertex to change the shape of the trapezoid.

A = (-2.94, 1.86)
P = (4.74, 1.9)
R = (-0.74, 4.84)
a = Segment(A, P)
b = Line(R, a)
T = Point(b)
c = Segment(R, T)
poly1, a_1, b_1, d, c_1 = Polygon(A, P, T, R)
PR = Segment(R, P)
AT = Segment(T, A)
O = Intersect(PR, AT)
e = Segment(R, O)
f = Segment(O, P)
g = Segment(O, T)
h = Segment(O, A)
α = Angle(R, O, A)
i = Segment(R, T)