Answer:
2. obtuse
Explanation:
The side ratios of an isosceles right triangle are ...
1 : 1 : √2
Using a scale factor of 2, these would be ...
2 : 2 : 2√2 ≈ 2.828
Thus the long side of the given triangle is longer than necessary for a right triangle. That means, the opposite angle is larger than 90°.
The triangle is obtuse.
_____
You can find the exact value of the angles using the law of cosines. For the purpose of classifying the triangle, you need to know the angle opposite the longest side.
∠C = arccos((a²+b²-c²)/(2ab)) = arccos(((4+4-9)/(2·2·2)) = arccos(-1/8)
The cosine is negative only for angles greater than 90°, so the triangle is obtuse.