What defines an equilateral triangle?

An equilateral triangle is defined specifically by having all three sides of equal length. This characteristic is foundational to the definition of equilateral triangles, as it not only influences the triangle’s shape but also relates directly to its angles. In an equilateral triangle, each internal angle measures 60 degrees, reinforcing the notion of equality in both sides and angles.

The other options do not capture the essence of an equilateral triangle. Two sides equal refers to isosceles triangles, while saying no sides equal describes scalene triangles. Additionally, stating that the properties of an equilateral triangle are dependent on the angles does not define its structure accurately, as it is the equality of the sides that primarily distinguishes it as an equilateral triangle. Thus, the proper understanding revolves around the fact that an equilateral triangle is characterized by having all three sides equal.