You may have correctly determined that the reference angle is $\displaystyle{{45}}^{\circ}\usepackage{cmbright}\Huge\$ and found $\displaystyle{{\tan{{45}}}}^{\circ}\usepackage{cmbright}\Huge\$ , but you made a mistake with the sign. Use the signs of x and y in the second quadrant to determine the sign of tangent, remembering that

$\displaystyle{\tan{\theta}}=\frac{{y}}{{x}}\usepackage{cmbright}\Huge\$ . The correct answer is $\displaystyle-{1}\usepackage{cmbright}\Huge\$ .