Please help me ab and ac are two tangent segment to the circle at b and c ..if m(<a)= 60 m(<dbc) = 85 and the area of triangle is 9root3 find perimeter of triangle

The pyraminx is a rubik's cube-type toy in the shape of a tetrahedron. the pyraminx shown below has edges 15\,\text{cm}15cm long and vertical height h=12.2\,\text{cm}h=12.2cm. the triangle drawn with dashed lines is a right triangle. what is the distance rr? round your answer to the nearest tenth.