Question

which is a correct classification for this triangle?
○ acute triangle
○ obtuse triangle
○ right triangle
○ equiangular triangle

Explanation:

Step1: Calculate the third angle

The sum of angles in a triangle is $180^\circ$. Let the third angle be $x$.
$$x = 180^\circ - 31^\circ - 59^\circ$$
$$x = 90^\circ$$

Step2: Classify the triangle

A triangle with one $90^\circ$ angle is a right triangle.

Answer:

right triangle