Answer
A triangle can have these lengths for its sides.
Work Step by Step
Using the Triangle Inequality Theorem, we need to see if the sum of each of the combinations of two sides is greater than the other side:
$11 + 12 > 15$ --> This statement is true.
$12 + 15 > 11$ --> This statement is true.
$11 + 15 > 12$ --> This statement is true.
A triangle can have these lengths for its sides because all combinations of two sides added together are greater than the third side.