Now, in ∆ABC,
there can be 3 cases
- All angles are acute
- One angle is right angle (90°)
- One angle is greater than 90° (i.e one angle is obtuse)
If all angles are acute, it is an acute angled triangle.
If one angle is right angle, it is a right angled triangle.
If one angle is greater than 90°, it is an obtuse angled triangle.