Question

Is it possible for a triangle to have sides with the given lengths? Explain. 5 in., 8 in., 15 in.

Answer 1

Hello.
No, it is not. With a triangle, the sum of 2 lengths of any 2 sides will always be greater than the third side.
In the problem 5 + 8 is 13, which is less than 15. So this cannot be a triangle.

Answer 2

Triangle Inequality Theorem

the sum of two side lengths of a triangle is always greater than the third side.

5+8=13 
your answer = no