Question 891264
{{{S/C=11/5}}}
{{{5S=11C}}}
{{{S=(11/5)C}}}
.
.
.
{{{S+A=180}}}
{{{C+A=90}}}
Substracting,
{{{S-C=90}}}
Substituting,
{{{(11/5)C-C=90}}}
{{{(6/5)C=90}}}
{{{C=(5/6)(90)}}}
{{{C=75}}}
Then,
{{{A=90-75}}}
{{{A=15}}}