Explanation:
this is simply per definition.
it is an obtuse triangle, because one angle (B) is larger than 90°.
it is a scalene triangle, because all 3 sides have different lengths.
"acute" would mean that all 3 angles are smaller than 90°.
"right" or "right-angled" would mean that one angle is exactly 90°.
"equilateral" would mean that all 3 sides are equally long.
"isoceles" would mean that 2 sides are equally long.