$\mathrm{}{180}^{\circ }$

$\mathrm{}{270}^{\circ }$

$\mathrm{}{360}^{\circ }$

$\mathrm{}{450}^{\circ }$

$\beta =\alpha +\gamma$

$\alpha +\beta +\gamma ={180}^{\circ }$

$\beta +\gamma -\alpha ={90}^{\circ }$

$\alpha +\beta -\gamma ={90}^{\circ }$

$2$个

$3$个

$4$个

$5$个

$\mathrm{}{15}^{\circ }$

$\mathrm{}{20}^{\circ }$

$\mathrm{}{25}^{\circ }$

$\mathrm{}{30}^{\circ }$

$1$

$\mathrm{}\frac{9}{4}$

$4$

$\mathrm{}\frac{36}{25}$