AOB is a quadrant with radius 6 and PQRO is a square with side =5.Then find the area of shaded region.

Join ON and OM

If we find angle NOR, we will also know angle MON.

but cosNOR= 5/6

So now we can easily find out arcNOM area and also remaining area consists of congruent triangles whose lengths are known. So just add all these areas and you will have your final answer!