a_r:

a_s:

b_r = 6.5 (slider from 0 to 50, step 0.1)
R = Intersect(xAxis, yAxis)
A = Point(yAxis)
t = Line(R, A)
α = 0.9599310885968813 rad (slider from 0 to 90°, step 1°)
B = (3, 0)
B' = Rotate(B, (-α), R)
β_{1} = Angle(B', R, B)
s = Line(R, B')
β = 0.3839724354387525 rad (slider from 0 to 90°, step 0.017453292519943295)
C = (1, 0)
C' = Rotate(C, β, R)
γ = Angle(C, R, C')
f = Line(R, C')
D: (b_r, 0)
r = Line(D, f)
T = Intersect(s, r)
S = Intersect(t, r)
t1, t_1, r_1, s_1 = Polygon(R, S, T)