Question 1073306
First off, B cannot be greater than 90 since,
{{{A+B>180}}} and it's required that,
{{{A+B+C=180}}}
Use the law of sines to calculate B.
{{{sin(B)/b=sin(A)/a}}}
{{{sin(B)/45.3=sin(128.8)/20.8}}}
{{{sin(B)=1.697}}}
This triangle is not possible.