oh it says integer lengths... DOH
\(3 < x < 3 \sqrt{5} \approx 6.7\\ \text{That gives you 4, 5, and 6}\)
4 gives you an angle of about 36.36 degrees
5 gives you an angle of about 56.25 degrees
6 gives you an angle of about 75.53 degrees
all 3 are acute triangles