A trapezoid is defined as a four-sided figure (quadrilateral) with at least one pair of parallel sides. By traditional definitions, a trapezoid can indeed have one right angle, but having three right angles introduces some interesting geometric implications.
If a trapezoid were to have three right angles, the fourth angle would necessarily have to be a right angle as well to satisfy the properties of a quadrilateral (the sum of all angles in a quadrilateral must equal 360 degrees). This implies that the trapezoid would actually be a rectangle, because all angles are equal to 90 degrees, and opposite sides are equal and parallel.
In conclusion, a trapezoid cannot have three right angles without also having a fourth right angle, which qualifies it as a rectangle instead. Therefore, while it might initially seem possible, upon deeper examination, it isn’t feasible for a standard trapezoid to exist with three right angles.