In a △ABC, a=1 and the perimeter is six times the A.M of the sines of the angles then measure of ∠A is
1+b+c=6 sin A+sin B+sin C3 =2(12R+b2R+c2R)=1R(1+b+c) ∴R=1(∵1+b+c≠0) So, 1sin A=2R=2⇒A=π6