Theory to know when answering this question:
1. The sum of the angles in a quadrilateral (shape with four sides) is 360°
2. Similar shapes have the same angles
Point 1 tells us that ∠P+∠Q+∠S+∠R=360
Point 2 tells us that ∠F=∠P, ∠G=∠Q, ∠J=∠S, and ∠H=∠R.
Radius = √75 or 5√3 or 8.7
This forms a right triangle meaning you can use Pythagorean Theorem to solve for the missing side which, in this case, will equal the radius.
Let a = radius
a² + b² = c²
a² + 11² = 14²
a² + 121 = 196
a² = 75
a = √75 = 5√3 ≈ 8.7