Question 364244
By defintion,
{{{A+S=180}}}
.
.
.
{{{A=9+(1/2)S}}}
Substitute,
{{{9+(1/2)S+S=180}}}
{{{18+S+2S=360}}}
{{{3S=342}}}
{{{highlight(S=114)}}}degrees
Then,
{{{A=9+(1/2)(114)}}}
{{{A=9+57}}}
{{{highlight(A=63)}}}degrees