Теорема cos:
BC^2=AB^2 + AC^2 -2AB*AC*cos BAC
BC^2=9 +16 - 2*3*4*cos 60= 25- 24*1/2=25 - 12 = 13
BC = корень(13)
Теорема cos:
BC^2=AB^2 + AC^2 -2AB*AC*cos BAC
BC^2=9 +16 - 2*3*4*cos 60= 25- 24*1/2=25 - 12 = 13
BC = корень(13)