Răspuns :
1 a)
Cf teorema Pitagora : cateta^2+Cateta^2=ipotenuza^2 =>
AC^2+AB^2=BC^2 =>AC^2 = 400-256=144 => AC=rad144=12
sinC=AB/BC = 16/20=4/5
cosC=AC/BC = 12/20=3/5
tgB=AC/AB=12/16=3/4
ctgB=AB/AC=16/12=4/3
1b)
BC=rad(6^2+36*3)=rad(4*36)=12
sinB=AC/BC = 6rad3/12=rad3/2
cosB=AB/BC = 6/12=1/2
tgC=AB/AC = 6/(6rad3)=1/rad3
ctgC=AC/AB = 6rad3/6=rad3