5. Zadatak

Slika

$\triangle ABD$ $$\begin{aligned}\frac\alpha2+\frac\beta2+162^\circ&=180^\circ\\\frac\alpha2+\frac\beta2&=18^\circ\\\alpha+\beta&=36^\circ\end{aligned}$$

$\triangle ABC$ $$\begin{aligned}\alpha+\beta+\gamma&=180^\circ\\36^\circ+\gamma&=180^\circ\\\gamma&=144^\circ\end{aligned}$$