We are told that D is the incenter of the triangle. This means that it is the point of concurrency of the angle bisectors.
Note that the segments connecting D with the sides, DT, DS, and DR are perpendicular to the sides. This means that their lengths are the distance from each side to the incenter. According to the Incenter Theorem, the incenter of a triangle is equidistant from its sides. Therefore, their lengths are equal.
DT=DS=DR
Since we are given the expression for the lengths of DR and DT, we can equate them.
DR= DT ⇒ x= 5
We found that x=5.
