To classify the triangle based on its angles:
- An acute triangle has all angles less than 90°.
- A right triangle has one angle equal to 90°.
- An obtuse triangle has one angle greater than 90°.
In this case, the triangle has angles measuring 46°, 51°, and 83°. Since all angles are less than 90°, this triangle is classified as an acute triangle.
So, the correct response is acute triangle.