A triangle is classified based on its angles.
- Acute Triangle: All angles are less than 90 degrees.
- Right Triangle: One angle is exactly 90 degrees.
- Obtuse Triangle: One angle is greater than 90 degrees.
In this triangle, the angles are 46°, 51°, and 83°. All of these angles are less than 90 degrees, so the triangle is an acute triangle.
Thus, the correct response is acute triangle.