Question

classifying triangles classify the triangle by its angles and by its sides. 18. l m 120° n

Explanation:

Step1: Classify by angles

An obtuse angle is an angle greater than \(90^{\circ}\) but less than \(180^{\circ}\). Since \(\angle M = 120^{\circ}\) (an obtuse angle), the triangle is an obtuse triangle.

Step2: Classify by sides

No information about side lengths is given to suggest it is equilateral (all sides equal) or isosceles (at least two sides equal). So, assume it is scalene (all sides of different lengths) based on no - side - length equality indication.

Answer:

By angles: obtuse triangle. By sides: scalene triangle.