Triangle Area and Circumradius Calculation

In triangle ABC, angle A measures 60 degrees and side a (opposite angle A) measures 12 units. The triangle is inscribed in a circle whose radius is R. Calculate the area of triangle ABC, and then find the value of $R$. Finally, compute the length of side b (opposite angle B) using the Law of Sines. Present your answer as a decimal value accurate to three decimal places.