Which statement best defines a rhombus?

Which statement best defines a rhombus?

• A. A parallelogram with four congruent sides
• B. A rectangle with equal diagonals
• C. A trapezoid with one pair of parallel sides
• D. A square

Answer: (A)

The main idea is that a rhombus is a parallelogram with all four sides equal in length. That combination—two pairs of parallel sides plus four congruent sides—gives the diamond-like shape while keeping the parallelogram properties intact. This definition is broad enough to include all rhombuses, including squares, which are rhombuses with right angles. The other descriptions don’t capture the full idea: describing it as a rectangle with equal diagonals points to a rectangle (diagonals are equal there) and doesn’t require all sides to be equal; calling it a trapezoid refers to a shape with only one pair of parallel sides, not two; while a square is indeed a rhombus, defining it as such would miss rhombuses that aren’t squares.

The main idea is that a rhombus is a parallelogram with all four sides equal in length. That combination—two pairs of parallel sides plus four congruent sides—gives the diamond-like shape while keeping the parallelogram properties intact. This definition is broad enough to include all rhombuses, including squares, which are rhombuses with right angles. The other descriptions don’t capture the full idea: describing it as a rectangle with equal diagonals points to a rectangle (diagonals are equal there) and doesn’t require all sides to be equal; calling it a trapezoid refers to a shape with only one pair of parallel sides, not two; while a square is indeed a rhombus, defining it as such would miss rhombuses that aren’t squares.