<spanclass=′latex−bold′>(a)</span> On the sides of triangle ABC we consider the points M∈BC, N∈AC and P∈AB such that the quadrilateral MNAP with right angles ∠MNA and ∠MPA has an inscribed circle. Prove that MNAP has to be a kite.
<spanclass=′latex−bold′>(b)</span> Is it possible for an isosceles trapezoid to be orthodiagonal and circumscribed too? (Călin Udrea)