Answer:
The smallest whole number length is 12
Explanation:
The sum of any two sides of any triangle must be greater than the length of the third side.
In this case, the two smallest sides of the triangle must be greater than the third side to satisfy the statement above.
Let "x" = the length of the third side.
Our two smaller sides are "x" and "4", and their sum must be greater than 15.
x + 4 > 15
x > 15 - 4
x > 11