S=1/2ACBCsinC
16=5*8*sinc/2
16=20sinC
sinC=16/20=4/5
cosC=-sqrt(1-16/25)=-3/5
AB^2=5^2+8^2-2*5*8cosC=25+64-80cosC=89+80*3/5=137
ab=sqrt(137)
S=1/2ACBCsinC
16=5*8*sinc/2
16=20sinC
sinC=16/20=4/5
cosC=-sqrt(1-16/25)=-3/5
AB^2=5^2+8^2-2*5*8cosC=25+64-80cosC=89+80*3/5=137
ab=sqrt(137)