The side can not form a triangle because the sum of any two sides must be greater than the other side: 3 + 4 = 7 and this is not greater than 7
Also, in order for the sides to form a right triangle a² + b² = c² where c is the longest side
3² + 4² ? 7²
9 + 16 ? 49
25 ≠ 49
ANSWER: No, the numbers cannot be a right triangle side lengths