Which of the following is a property of an equilateral triangle?

A. Exactly two angles are of equal measure.
B. One of the angles measures more than 90 degrees.
C. Two of the angles measure 45 degrees.
D. All three sides are of equal length.



Answer :

An equilateral triangle is a special type of triangle where all three sides are of equal length. As a consequence of this, all three interior angles are also equal, each measuring 60 degrees.

Let's analyze each of the given choices to determine which one correctly describes a property of an equilateral triangle:

a) "Exactly two angles are of equal measure."
This is not accurate because, in an equilateral triangle, all three angles are equal, not just two.

b) "Two of the angles measure 45 degrees."
This is incorrect because, in an equilateral triangle, each of the three angles measures 60 degrees, not 45 degrees.

c) "One of the angles measures more than 90 degrees."
This is also incorrect because, by definition, an equilateral triangle has all angles measuring 60 degrees, none of which are greater than 90 degrees.

d) "All three sides are of equal length."
This statement is true. By definition, an equilateral triangle has all three sides of equal length.

Thus, the correct choice is:
d) All three sides are of equal length.