ParaPro Assesment Practice Exam

Which triangle has all angles measuring less than 90 degrees?

1. Obtuse triangle

2. Acute triangle

3. Right triangle

4. Equilateral triangle

The correct answer is: Acute triangle

An acute triangle is one in which all three interior angles are less than 90 degrees. This characteristic defines it distinctly from other types of triangles. In an acute triangle, because all angles are acute, the triangle does not have any right angles (which are exactly 90 degrees) or obtuse angles (which are greater than 90 degrees). For additional context, an obtuse triangle contains one angle that is greater than 90 degrees, making it impossible for all angles to be acute. A right triangle has one angle that is exactly 90 degrees, which also disqualifies it from being categorized as acute. An equilateral triangle, while each angle measures 60 degrees (and thus qualifies as acute), is specifically defined by all sides being equal rather than by the categorization based on the measurement of angles alone. Therefore, the acute triangle is the only option where all angles measure less than 90 degrees, highlighting its fundamental properties in triangle classification.