Correct. For an angle $\displaystyle\theta\usepackage{cmbright}\Huge\$ in standard position that intersects the unit circle at $\displaystyle{\left({x},{y}\right)}\usepackage{cmbright}\Huge\$ , we have $\displaystyle{\sin{\theta}}={y}\usepackage{cmbright}\Huge\$ . So $\displaystyle{{\sin{{270}}}}^{\circ}=-{1}\usepackage{cmbright}\Huge\$ .