C=180-60-45=75
由正弦定理,a÷sinA=c÷sinC
c=asinC÷sinA=3×sin75÷sin60
sin75=sin(30+45)=sin30cos45+cos30sin45=(√2+√6)/4
sin60=√3/2
c=(√6+3√2)/2
C=180-60-45=75
由正弦定理,a÷sinA=c÷sinC
c=asinC÷sinA=3×sin75÷sin60
sin75=sin(30+45)=sin30cos45+cos30sin45=(√2+√6)/4
sin60=√3/2
c=(√6+3√2)/2