Question 1064381
From the law of cosines,
{{{c^2=a^2+b^2-2abcos(C)}}}
{{{c^2=12^2+8^2-2(8)(12)cos(48)}}}
{{{c^2=144+64-192(.6691)}}}
{{{c^2=79.53}}}
{{{c=8.92}}}
From the law of sines,
{{{sin(C)/c=sin(B)/b}}}
{{{sin(48)/8.92=sin(B)/8}}}
{{{sin(B)=(8/8.92)sin(48)}}}
{{{sin(B)=0.6667}}}
{{{B=41.81}}}
So then,
{{{A+B+C=180}}}
{{{A+41.81+48=180}}}
{{{A=90.2}}}
Since {{{A>90}}}, obtuse.