The two given lengths (numbers) are a and b. 
(a = RG and b = SG in the figure)

Three Means:
  Arithmetic Mean (AM)
  Geometic Mean (GM)
  Harmonic Mean (HM)

Note:
  AH ≤ GM ≤ AM

a = 2.2 (slider from 0 to 12, step 0.1)
b = 7.1 (slider from 0 to 12, step 0.1)
R: (-1.0 * 1.0 * 1.0 * 1.0 * 1.0 * a, 0.0)
S: (b, 0.0)
c = Segment(R, S)
A = Midpoint(R, S)
d = Circle(A, S)
G = (0, 0)
e = OrthogonalLine(G, c)
B, M = Intersect(d, e)
f = Segment(A, M)
g = OrthogonalLine(A, c)
i = Segment(G, M)
h = OrthogonalLine(G, f)
H = Intersect(h, f)
j = Segment(G, H)
k = Segment(H, M)
l = Segment(R, G)
m = Segment(G, S)