Answer:
greater than 2
less than 28
Step-by-step explanation:
The sum of the lengths of the two shortest sides must be more than the length of the longest side. If x is the shortest side, ...
... x + 13 > 15
... x > 2
If x is the longest side, ...
... 13 +15 > x
... x < 28
Then the allowed range for the third side is ...
... 2 < x < 28
