Question 7
In convex quadrilateral $ABCD$
$$
\angle ADB + \angle ACB = \angle CAB + \angle DBA = 30^\circ \text{ and } AD = BC.
$$
Prove that segments $DB$, $CA$ and $DC$ form the sides of the right triangle.
$$
\angle ADB + \angle ACB = \angle CAB + \angle DBA = 30^\circ \text{ and } AD = BC.
$$
Prove that segments $DB$, $CA$ and $DC$ form the sides of the right triangle.