Question

R=? BC=3, cos A=1/2

Answer 1

2R = a/sin(A), a = BC

sin^2(A) + cos^2(A) = 1 <=> sin^2(A) + 1/4 = 1 <=> sin(A) = rad(3/4) <=> sin(A) = rad(3)/2

2R = 3*2/rad(3) <=> R = 3/rad(3) <=> R = rad(3)