Which statement correctly describes an isosceles triangle?

Which statement correctly describes an isosceles triangle?

• A. All three sides are equal
• B. No sides are equal
• C. Two sides are equal
• D. The angles are all equal

Answer: (C)

Two sides being equal in length defines an isosceles triangle. This means the triangle has exactly two sides that match, setting it apart from a triangle where all three sides are equal (equilateral) or where no sides are equal (scalene). A handy related fact is that the angles opposite those equal sides are also equal, which often helps with solving problems involving angles. The other descriptions describe different types: all three sides equal points to an equilateral triangle, no sides equal points to a scalene triangle, and having all angles equal would also indicate an equilateral triangle in a standard triangle.

Two sides being equal in length defines an isosceles triangle. This means the triangle has exactly two sides that match, setting it apart from a triangle where all three sides are equal (equilateral) or where no sides are equal (scalene). A handy related fact is that the angles opposite those equal sides are also equal, which often helps with solving problems involving angles. The other descriptions describe different types: all three sides equal points to an equilateral triangle, no sides equal points to a scalene triangle, and having all angles equal would also indicate an equilateral triangle in a standard triangle.