等边三角形a/sinB=b/sinC=c/sinA=(a+b+c)/(sina+sinb+sinc)
a/sina=b/sinb=c/sinc=(a+b+c)/(sina+sinb+sinc)
所以a/sina=b/sinb=c/sinc=a/sinB=b/sinC=c/sinA
c=b=a
等边三角形a/sinB=b/sinC=c/sinA=(a+b+c)/(sina+sinb+sinc)
a/sina=b/sinb=c/sinc=(a+b+c)/(sina+sinb+sinc)
所以a/sina=b/sinb=c/sinc=a/sinB=b/sinC=c/sinA
c=b=a