Classification of Triangles According to Angles

(i) If one angle of a triangle is a right angle, then it is called a right angled triangle. Note that the other two angles are acute.

(ii) If all the angles of a triangle are acute, then it is called an acute angled triangle.

(iii) If one angle of a triangle is obtuse, then it is called an obtuse angled triangle. Note that the other two angles are acute.