m = -4 (slider from -10 to 0, step 0.05)
B = (3.24, 4.88)
S = (1.66, 1.88)
k = Circle(S, B)
X = Point(k)
k_T = Semicircle(X, S)
k_1 = Circle(X, sqrt((-m)))
Y = Point(k)
t_1 = Line(X, Y)
t = Tangent(X, k)
r = Segment(X, S)
Q = Intersect(k_1, k_T, 2)
l = Circle(S, Q)
A = Intersect(l, t_1, 1)
a = Distance(A, X)
b = Distance(A, Y)
i: (a * b)
f = Segment(Q, S)