a)  $\alpha ={180}^o-{138}^o={42}^o$  

b)  $\beta ={180}^o-{80}^o-{52}^o={100}^o-{52}^o={48}^o$  

c)  $\gamma ={180}^o-{90}^o-{65}^o={90}^o-{65}^o={25}^o$  

d)  $\delta ={180}^o-{35}^o-{38}^o-{38}^o={145}^o-{38}^o-{38}^o={145}^o-{76}^o={69}^o$