A = [1,-2],\; B = [-3,3],\; C = [1,3] 

\left| AB \right| =\sqrt{\left(1-(-3) \right) ^{2}+\left(-2-3 \right) ^{2}}=\sqrt{41}

\left| AC \right| =\sqrt{\left(1-1 \right) ^{2}+\left(-2-3 \right) ^{2}}=\sqrt{25}=5

\left| BC \right| =\sqrt{\left(-3-(-1) \right) ^{2}+\left(3-3 \right) ^{2}}=\sqrt{16}=4

A = (1, -2)
B = (-3, 3)
C = (1, 3)
t1, b, a, c = Polygon(A, C, B)
c_1 = SurdText(c)
b_1 = SurdText(b)
a_1 = SurdText(a)
γ = Angle(A, C, B)