In a triangle, if the three sides are of equal length, it is a/an __________ triangle.

In a triangle, when all three sides are of equal length, it is classified as an equilateral triangle. This classification is based on the definition of triangle types. Each side being equal means that not only are the lengths the same, but the angles opposite each side are also equal, specifically 60 degrees each, making it a very symmetrical figure.

An isosceles triangle has at least two sides of equal length, but does not necessarily have all three sides equal. A right triangle is characterized by having one angle that measures 90 degrees, which does not pertain to the lengths of the sides. Lastly, a scalene triangle is defined by having all sides of different lengths, which directly contradicts the equality condition specified in the question. Hence, equilateral is the most accurate descriptor for a triangle where all three sides are the same.