Answer:
Option D.
![KR=17.2\ mm](https://img.qammunity.org/2020/formulas/mathematics/high-school/g1pdy2m0o129m55sz9597dyrguwl5vok6w.png)
Explanation:
we know that
The Centroid of a Triangle is the center of the triangle that can be calculated as the point of intersection of all the three medians of a triangle. The centroid divides each median in a ratio of
![2:1](https://img.qammunity.org/2020/formulas/mathematics/middle-school/61qtann1mbjxcw6ubi6a4rk74jwzdg59jr.png)
In this problem the point R represent the centroid of triangle JKL
therefore
![KR=(2/3)KM](https://img.qammunity.org/2020/formulas/mathematics/high-school/7r2i11shie3wmnsy7bbvi6uh5p34m5mmts.png)
substitute the value
![KR=(2/3)(25.8)=17.2\ mm](https://img.qammunity.org/2020/formulas/mathematics/high-school/49odvpjrg5qswaj14b0dhapegf87xvcjtq.png)