Question 1072172
I assume you mean {{{Y=12}}}.
So use the law of sines to find angle X.
{{{sin(Y)/y=sin(X)/x}}}
{{{sin(79)/12=sin(X)/10}}}
{{{sin(X)=(10/12)sin(79)}}}
{{{sin(X)=0.8180}}}
{{{X=54.9}}}
So then you know,
{{{X+Y+Z=180}}}
{{{54.9+79+Z=180}}}
{{{Z=46.1}}}