AB/sinC=BC/sinA
2BC/sinC=BC/sinA
sinC=2sinA
∫B = 60
∴C+A= 120
∴C= 120-A
∴sinc=sin( 120-a)=sin 120cosa-cos 120sina=2sina
√3/2 cosA+sinA/2=2sinA
√3/2 cosA=3/2sinA
√3cosA=3sinA
CosA =√3 square.
cos^2A= 1-sin^2A=3sin^2A
4sin^2A= 1
∵A & lt； 180
∴sina>； 0
Sina = 1/2
A=30
C= 120-A=90
Triangle ABC is a right triangle.