You probably set up the incorrect equation, $\displaystyle{{\sin{{48}}}}^{\circ}=\frac{{y}}{{10}}\usepackage{cmbright}\Huge\$ . The correct equation to use is $\displaystyle{{\cos{{48}}}}^{\circ}=\frac{{y}}{{10}}\usepackage{cmbright}\Huge\$ . Solve this equation for y and round off.