Question 1096621
{{{system(B=C+4,A=2B,A+B+C=180)}}}


{{{system(C=B-4,A=2B)}}}, substitute these.


{{{2B+B+(B-4)=180}}}

{{{4B-4=180}}}

{{{B-1=45}}}

{{{highlight(B=46)}}}--------you can use this to find A and C.