me assume that stuf shood be... tan(3pi/11) +4*sine(2pi/11)=sqrt(11)... pi=3.141592653589793238462643383279.... 3pi=9.42477795 & 3pi/11=0.856797995 radians... with 57.2957795130823208767981... degrees in 1 radian, get... tan(49.09090903 deg)=1.154061518... 2pi/11=6.2831853/11=0.571198663 radians=32.7272727 deg... sine(32.7272727 deg)=0.540640816... 4*0.540840816=2.162563268... 1.154061518 +2.162563268=3.316624786... sqrt(11)=3.31662479... look like 2 the same