Answer:
sometimes
Explanation:
If this is an "always, sometimes, never" kind of problem, the answer is sometimes.
An isosceles triangle can be an obtuse triangle sometimes (but might be right or acute. An obtuse triangle can be isosceles or may be scalene. An obtuse triangle cannot be a right triangle nor equilateral.
The names for triangles comes from their angles:
right, acute, obtuse;
OR from their sides:
scalene, isosceles, equilateral.