cos(A) \; = \;  \frac{ b² \; + \; c² \; - \; a² }{2bc } 

cos(B) \; = \;  \frac{ a² \; + \; c² \; - \; b² }{2ac } 

cos(C) \; = \;  \frac{ a² \; + \; b² \; - \; c² }{ 2ab} 

A = (-1.2738025316052042, 0.17547777405851503)
B = (0.006109733411242095, 0.9186526376164521)
C = (0.35517671477936436, 0.15671073204947625)
Tên đa giác1, c, a, b = Polygon(A, B, C)