设sinA/a=sinB/b=sinC/c=t
则(at)^2=(bt)^2+(ct)^2
a^2=b^2+c2
所以RT△
∠A=90°
2sinBsinC =2sinBsin(90°-B)=2sinBcosB =1
sin2B=1
2B=90°
B=45°
所以等腰直角三角形
设sinA/a=sinB/b=sinC/c=t
则(at)^2=(bt)^2+(ct)^2
a^2=b^2+c2
所以RT△
∠A=90°
2sinBsinC =2sinBsin(90°-B)=2sinBcosB =1
sin2B=1
2B=90°
B=45°
所以等腰直角三角形