Answer:
9 and 12
Explanation:
Pythagorean Theorem. One of the most common Pythagorean triples is 3, 4, 5 with 3 and 4 the legs and 5 the hypoenuse. That will make 9, 12, 15 anotther trible because you are tripling the side lengths. 12-9=3 so this triangle works.