c
\(\,1.5\,\, = \,\,\,\frac{{sin\,\,\left( {\frac{{A + A}}{2}} \right)}}{{sin\,\,\left( {\frac{A}{2}} \right)}}\,\, = \,\,\frac{{\sin \,\,A}}{{\sin \,\,\left( {\frac{A}{2}} \right)}}\)

\(1.5\,\,\sin \,\,\frac{A}{2}\,\, = \,\,2\,\,\sin \,\,\frac{A}{2}\,\,\cos \,\,\frac{A}{2}\,\, \Rightarrow \,\,\,0.75\,\, = \,\,\cos \,\,\left( {\frac{A}{2}} \right)\)

\(\frac{A}{2}\,\, = \,\,{41^ \circ }\, \Rightarrow \,\,A\,\, = \,\,{82^ \circ }\)