1. Obtuse; scalene
2. Acute; equilateral
3. Right; scalene
4. Acute or obtuse; isosceles
Explanation:
Obtuse is an angle >90 degrees
Acute is an angle <90 degrees
Right is an angle equal to 90 degrees
Equilateral means all sides are equal
Isosceles means two sides are equal
Scalene means no sides are equal