Final answer:
To find RS, subtract the length of ST from RT: RS = RT - ST. Given values result in RS = 48.
Step-by-step explanation:
To find RS when given ST = 13 and RT = 61, we can use the fact that RS + ST = RT if the points R, S, and T are aligned in a straight line.
Therefore, RS = RT - ST.
Substituting the given values, we find RS = 61 - 13.
Thus, RS = 48.