test1
Author: Raymond Moché

α=\widehat{ACH}

α = 60 (slider from 0 to 360, step 2)
O = (0, 0)
D = 2 (slider from 0 to 7.4, step 0.2)
x_0: 3.14159 α D / 360
C: (x_0, D / 2)
c = Circle(C, D / 2)
H = Intersect(c, xAxis, 1)
A = Rotate(H, -3.14159 α / 180, C)
a = Segment(H, C)
b = Segment(C, A)
β = Angle(A, C, H)
OH = Distance(O, H)
K: (x_0, -0.55)
T3: "L=" + OH + "cm"