Question

What is an equilateral triangle?

• A. Whose three interior angles are equal
• B. Whose three walls are big and small
• C. Whose two sides are equal
• D. None of these

Hint:

All angles in an equilateral triangle are equal to \(60^\circ\), and all sides are the same length.

Answer 1

The Correct Option is A

Step 1: Definition of Equilateral Triangle
An equilateral triangle is a triangle in which all three sides are equal in length.
By the properties of triangles, if all sides are equal, then all angles are also equal.

Step 2: Use angle property
Each interior angle of an equilateral triangle is: \[ \frac{180^\circ}{3} = 60^\circ \] So, not only are the three sides equal, but the three interior angles are also equal — each measuring \( 60^\circ \).

Step 3: Eliminate wrong options
- (B): "Walls" is irrelevant and vague in geometric context.
- (C): This describes an isosceles triangle, not equilateral.
- (D): Incorrect — there is a valid correct definition.
\[ \boxed{\text{Correct Answer: (A) Whose three interior angles are equal}} \]