r

Octógono

c = 1.9 (slider from 0.2 to 5, step 0.1)
A_1 = Point(a)
d = Circle(A_1, c)
B_1 = Intersect(d, a, 2)
A = (1.8094533761481906, 5.119916504448796)
B = (0.3446869488115359, 2.895641559233877)
C = (2.1168734905274897, 1.1777056259378014)
D = (4.395399044162286, 2.8233074146740424)
E = (4.5219837971419965, 4.432742131130365)
polígono1, a_1, b, c_1, d_1, e = Polygon(A, B, C, D, E)
f = Ray(E, A)
g = Ray(A, B)
h = Ray(B, C)
i = Ray(C, D)
j = Ray(D, E)
F = Point(j)
k = Circle(A, Segment[E, F])
p = Circle(B, Segment[E, F])
q = Circle(C, Segment[E, F])
r = Circle(D, Segment[E, F])
G = Intersect(k, f, 2)
H = Intersect(p, g, 2)
I = Intersect(r, i, 2)
J = Intersect(q, h, 2)
α_1 = Angle(F, E, A)
β_1 = Angle(G, A, B)
γ_1 = Angle(H, B, C)
δ_1 = Angle(J, C, D)
ε_1 = Angle(I, D, E)
K = (11.809648861545355, 1.955297679956025)
l = Line(K, i)
m = Line(K, d_1)
n = Line(K, e)
s = Line(K, a_1)
t = Line(K, b)
e_1 = Circle(K, Segment[E, F])
L = Intersect(e_1, l, 2)
M = Intersect(e_1, m, 2)
N = Intersect(e_1, n, 2)
O = Intersect(e_1, s, 2)
P = Intersect(e_1, t, 2)
ζ = Angle(L, K, M)
η = Angle(M, K, N)
θ = Angle(N, K, O)
ι = Angle(O, K, P)
κ = Angle(P, K, L)
b_1 = Segment(D, I)
f_1 = Segment(E, F)
g_1 = Segment(A, G)
h_1 = Segment(B, H)
i_1 = Segment(C, J)
j_1 = Segment(K, M)
k_1 = Segment(K, L)
l_1 = Segment(K, P)
m_1 = Segment(K, O)
n_1 = Segment(K, N)
α = Angle(A, E, D)
β = Angle(B, A, E)
γ = Angle(C, B, A)
δ = Angle(D, C, B)
ε = Angle(E, D, C)
λ: α + β + γ + δ + ε
texto1: "A soma dos ângulos internos de um 
polígono convexo com n lados é igual 
a (n-2)x180º:
" + α + "+" + β + "+" + γ + "+" + δ + "+" + ε + "=(5-2) x 180º = 540º "