Choose a chord length

Slide the blue dot

A_1 = (12, 0)
p: y = 0
A = Point(p)
c = Circle(A_1, A)
k = Segment(A, A_1)
d = Semicircle(A, A_1)
chord = 6 (slider from 0 to 10, step 0.1)
e = Circle(A_1, chord)
C = Intersect(d, e, 1)
f = Segment(C, A_1)
I = Midpoint(k)
j = OrthogonalLine(I, k)
J = Intersect(d, j, 1)
l = OrthogonalLine(A_1, k)
m = OrthogonalLine(C, k)
n = OrthogonalLine(J, j)
K = Intersect(m, n)
L = Intersect(l, n)
M = Intersect(m, k)
q1, m_1, a, l_1, k_1 = Polygon(M, A_1, L, K)
text1: "Area = " + (LaTeX[q1]) + ""
M' = Translate(M, (0, 0))
B = Translate(A_1, (0, 0))
L' = Translate(L, (0, 0))
K' = Translate(K, (0, 0))
q1', m', b, l', k' = Polygon(M', B, L', K')