TRUE, a triangle with these side lengths is possible.
There is a theorem in geometry stating that the third side of a triangle must be shorter than the sum of the two current sides and longer than the difference of the two current sides. This theorem can be represented by the following inequality:
x = third side
1<x<9
8 falls right into the range, therefore, it is possible to have a triangle with sides 4 in, 5 in, and 8 in.