Tehtävä tunnilta, taittumissiirto.

AO=2.5

OAC=55

cos(OAC)=OA/AC

cos(55)=2.5/AC

AC*cos(55)=2.5

AC=2.5/cos(55)

AC=4.358616989052744

sin(b)/sin(a)=1/1.5

a=55

sin(b)/sin(55)=1/1.5

b=33.09995908918575

cos(b)=OA/AB

AB*cos(b)=2.5/AC

AB=2.5/cos(b)

AB=2.984293876605293

OC=sqrt(AC^2-OA^2)

OC=sqrt(4.358616989052744^2-2.5^2)=3.570370016855285

OB=sqrt(AB^2-OA^2)

OB=sqrt(2.984293876605293^2-2.5^2)=1.629726953186897

BC=OC-OB=1.940643063668388≈1.94cm