Question

What is a acute triangle ?

Answer 1

Acute triangles are triangles that have no right angles and no obtuse angles. This means that all of the angels of the triangle are acute. When classifying triangles, if all of the angles of the triangle are acute, then the triangle is acute. Triangles always have at least 2 sets of acute angles.

Answer 2

It is a triangle where all the angles are acute.

An acute angle is an angle measuring less than 90 degress.

Note that, since the sum of the interior angles of a triangle is 180, a triangle can have at most one non-acute triangle. In fact, if a triangle had two angles, $\alpha$ and $\beta$ both exceeding 90 degrees, their sum alone would exceed 180 degress, which is impossible.