A triangle has side lengths of 8cm, 15cm, and 17cm.classify it as acute, obtuse, or right

Answer 1

8^2 + 15^2 = 17^2
so, a right triangle

You would do well to recognize a few basic Pythagorean triples, such as
3-4-5, 5-12-13, 8-15-17, 7-24-25
and their multiples