1) CosB=Cos(90-A)=SinA=0,1;
2) (SinA)^2=1-(CosA)^2;
(SinA)^2=1-(7/25)^2;
SinA=√576/625=24/25=0,96;
3) CosA=AC/AB;
0,5=AC/8;
AC=0,5*8=4;
4) CosA=AC/AB=4/8=0,5;
5) SinA=0,5; A=30°;
CosA=AC/AB;
Cos30°=8/AB;
AB=8 : √3/2=16/√3;
S=AB*AC*SinA/2;
S=8*16*0,5/2√3=32/√3;
S=AB*CH/2;
32/√3=16*CH/2*√3;
8CH=32;
CH=4;