I don't know.
Let's find out.
If it IS a right triangle, then . . .
(square of the shortest side)
plus
(square of the medium side)
adds up to
(square of the longest side).
Shortest side = 3.5 . Its square is (3.5)² = 12.25
Medium side = 4.5 . Its square is (4.5)² = 20.25
(square of the shortest side) + (square of the medium side) = 32.5 .
Longest side = 5.5 . Its square is (5.5)² = 30.25 .
30.25 is NOT equal to 32.5 .
So this is NOT a right triangle.