Which triangle type has all angles measuring less than 90 degrees?

The triangle type characterized by all angles measuring less than 90 degrees is known as an acute triangle. In an acute triangle, each of the three interior angles is acute, meaning they are all less than 90 degrees. This property distinguishes acute triangles from right triangles, which have one angle exactly equal to 90 degrees, and obtuse triangles, which contain one angle greater than 90 degrees.

While isosceles triangles are defined by having at least two sides of equal length and can be acute, right, or obtuse, the defining characteristic used in this question pertains specifically to the relationship of the angles within the triangle itself. Thus, the correct identification of all angles being less than 90 degrees confirms the triangle is acute.