Incorrect. Remember that acute angles measure between $\displaystyle{{0}}^{\circ}\usepackage{cmbright}\Huge\$ and $\displaystyle{{90}}^{\circ}\usepackage{cmbright}\Huge\$ , right angles measure exactly $\displaystyle{{90}}^{\circ}\usepackage{cmbright}\Huge\$ , obtuse angles measure between $\displaystyle{{90}}^{\circ}\usepackage{cmbright}\Huge\$ and $\displaystyle{{180}}^{\circ}\usepackage{cmbright}\Huge\$ , and a straight angle measures $\displaystyle{{180}}^{\circ}\usepackage{cmbright}\Huge\$ .