Question 22Inside a right circular cone with base radius $5$ and height $12$ are three congruent spheres each with radius $r.$ Each sphere is tangent to the other two spheres and also tangent to the base and side of the cone. What is $r?$$\dfrac{3}{2}$$\dfrac{90-40\sqrt{3}}{11}$$2$$\dfrac{144-25\sqrt{3}}{44}$$\dfrac{5}{2}$