Point

a = 16.2 (slider from 5 to 18, step 0.1)
A2: (5, 4.2)
A3: (7.4, 2.84)
A4: (9.8, 2.14)
A5: (13, 1.62)
A6: (18, 1.17)
f = PolyLine(A2, A3, A4, A5, A6)
A: (a, 0)
g = Line(A, yAxis)
B = Intersect(g, f)
h = Line(B, xAxis)
C = Intersect(h, yAxis)