Question

Equilateral triangle QRS is shown below. What can be determined about the angles in triangle QRS?

A. All angles are acute and measure 60°.
B. One angle is a right angle that measures 90°.
C. One angle is an obtuse angle that measures more than 90°.
D. The sum of the three angles equals more than a straight angle.

Answer 1

In an equilateral triangle QRS, all angles are acute and each measures 60 degrees. The sum of angles in any triangle is 180 degrees, making option A correct for triangle QRS.

Step-by-step explanation:

When we consider an equilateral triangle like triangle QRS, we know that all three sides are of equal length. By definition, an equilateral triangle also has all three internal angles equal. Since the sum of the angles in any triangle adds up to 180 degrees, each angle in an equilateral triangle measures 60 degrees. Therefore, we can determine that for triangle QRS, all angles are acute and measure 60°.

Option A is correct because all angles in an equilateral triangle are equal and acute, which means they are less than 90 degrees. Options B and C can be disregarded because they suggest the presence of right or obtuse angles, which is not possible in an equilateral triangle. Option D is incorrect as it suggests the sum of the angles is more than 180 degrees, but the sum of angles in any triangle is exactly 180 degrees.