What type of triangle has all angles measuring less than 90 degrees?

A triangle with all angles measuring less than 90 degrees is classified as an acute triangle. In geometry, an acute angle is defined as one that measures less than 90 degrees. Therefore, if all three angles of a triangle fit this criterion, the triangle is categorized as acute.

This classification helps distinguish acute triangles from other types, such as right triangles, which contain one angle that is exactly 90 degrees, and obtuse triangles, which have one angle greater than 90 degrees. Additionally, while a scalene triangle refers to the side lengths of the triangle being all different, it does not inherently describe the angles. Thus, it cannot be considered a fitting answer for the question regarding angles. Therefore, an acute triangle is the correct response, as it specifically pertains to triangles with all angles less than 90 degrees.