An isosceles trapezoid is defined as which?

An isosceles trapezoid is defined as which?

• A. A trapezoid whose parallel sides are congruent
• B. A trapezoid whose nonparallel opposite sides are congruent
• C. A quadrilateral with equal diagonals
• D. A rectangle with equal bases

Answer: (B)

A trapezoid has one pair of parallel sides, called the bases. If the other, nonparallel sides are equal in length, that shape is an isosceles trapezoid. That makes the two legs congruent, which is exactly what describes the figure in this case. From this definition, you can also expect the base angles to be equal and the diagonals to be equal as nice follow-up properties. The idea that the bases themselves are equal or that the figure is a rectangle doesn’t define an isosceles trapezoid, and saying the diagonals are equal is a consequence, not the defining feature.

A trapezoid has one pair of parallel sides, called the bases. If the other, nonparallel sides are equal in length, that shape is an isosceles trapezoid. That makes the two legs congruent, which is exactly what describes the figure in this case. From this definition, you can also expect the base angles to be equal and the diagonals to be equal as nice follow-up properties. The idea that the bases themselves are equal or that the figure is a rectangle doesn’t define an isosceles trapezoid, and saying the diagonals are equal is a consequence, not the defining feature.