Se foloseste Pitagora generalizata (Teorema cosinusului)
AC^2=AB^2+BC^2-2xABxBCx cos (AB,BC)
Inlocuim si obtinem
7=16+3-8x(sqrt3)xcos(AB,BC)
9=8(sqrt3)xcos(AB,BC)
9/(8sqrt3)=cos(B)
9sqrt3/24=cos(B)
3sqrt3/8=cos(B)
0.649...=cos(B)
Folosesti tabelele trigonometrice si aflii unghiul B