Question

which quadrilateral is not a trapezoid?

Explanation:

Step1: Recall trapezoid definition

A trapezoid is a quadrilateral with at least one pair of parallel sides.

Step2: Analyze each figure

• Top - left: Has one pair of parallel sides (bases of trapezoid).
• Top - right: Check sides. No pair of sides is parallel (all sides seem non - parallel when visually inspected, angles and side orientations don't suggest parallelism).
• Bottom - left: Has one pair of parallel sides (the two horizontal - like sides if we consider the right angle, or the slant and top/bottom? Wait, actually, it's a trapezoid (maybe a right trapezoid) with one pair of parallel sides.
• Bottom - right: Is a parallelogram, which has two pairs of parallel sides, so it is a trapezoid (since it has at least one pair of parallel sides).

Answer:

The quadrilateral in the top - right (the non - parallel - sided quadrilateral among the four) is not a trapezoid.