We have a DM line that has a value of 25 in turn, this DM line can be formed by the DG+GM lines
DG measures r+3 and GM measures 4r-28 and we already know that DM=DG+GM
Let's replace the values, operate, and clear r
[tex]\begin{gathered} DM=DG+GM \\ 25=(r+3)+(4r-28) \\ 25=5r-25 \\ 25+25=5r \\ \frac{50}{5}=r \\ r=10 \end{gathered}[/tex]
The answer is r=10
