Final answer:
The radius of the inscribed circle of AHJK is 3x.
Step-by-step explanation:
The radius of the inscribed circle of AHJK can be found by using the information given. We know that AB = 3x and AC = 3R. Since AB is a tangent to the inscribed circle, it is perpendicular to the radius of the circle at the point of tangency. Therefore, AB is a radius of the inscribed circle. Therefore, the radius of the inscribed circle is 3x.