Neka je
![ABCD](/media/m/9/c/e/9ce25711ba18d9663b73c3580de4bf5a.png)
konveksni četverokut takav da vrijedi
![\angle{BAD}=90^\circ, \qquad \angle{BAC}=2\angle{BDC} \quad \text{i} \quad \angle{DBA}+\angle{DCB}=180^{\circ}.](/media/m/4/a/0/4a06c736e12807d54c7058e634711bd4.png)
Odredi mjeru kuta
![\angle{DBA}](/media/m/a/1/b/a1bda73d3be215d4b73e933f9010fde0.png)
.
%V0
Neka je $ABCD$ konveksni četverokut takav da vrijedi $$\angle{BAD}=90^\circ, \qquad \angle{BAC}=2\angle{BDC} \quad \text{i} \quad \angle{DBA}+\angle{DCB}=180^{\circ}.$$
Odredi mjeru kuta $\angle{DBA}$.