Answer: The required possible value of y are 15 and -9.
Step-by-step explanation: Given that the point R has co-ordinates (1,3) and point S has coordinates (6,y). Also, the distance from R to S is 13 units.
We are to find the possible values of y.
Distance formula : The distance between the points (a, b) and (c, d) is given by

Therefore, we get
![√((6-1)^2+(y-3)^2)=13\\\\\Rightarrow 25+(y-3)^2=169~~~~~~~~~~~~[\textup{Squaring both sides}]\\\\\Rightarrow (y-3)^2=169-25\\\\\Rightarrow (y-3)^2=144\\\\\Rightarrow y-3=\pm12~~~~~~~~~~~~~~~~~~~[\textup{Taking square root on both sides}]\\\\\Rightarrow y=12+3,~~-12+3\\\\\Rightarrow y=15,-9.](https://img.qammunity.org/2017/formulas/mathematics/high-school/v9cdoh30m8c5trpyhw65b3c9ee32uka4mr.png)
Thus, the required possible value of y are 15 and -9.