Question

1. which of the following does not hold true for an equilateral triangle? all sides are equal length all angles measure 60 degrees all interior angles add up to 180 degrees only two sides are equal length

Explanation:

An equilateral triangle is defined as a triangle with all three sides of equal length. By the properties of triangles, the sum of interior angles of any triangle is 180 degrees, and in an equilateral triangle, since all sides are equal, all angles are equal (each being 60 degrees as \(180\div3 = 60\)). The option "Only two sides are equal length" describes an isosceles triangle, not an equilateral triangle.

Answer:

D. Only two sides are equal length (assuming the options are labeled A to D with A: All sides are equal length, B: All angles measure 60 degrees, C: All interior angles add up to 180 degrees, D: Only two sides are equal length)