Может ли параллельная проекция параллелограмма быть трапецией
Yes, a parallel projection of a parallelogram can indeed be a trapezoid. A trapezoid is defined as a quadrilateral with one pair of parallel sides. In a parallelogram, both pairs of opposite sides are parallel, so a parallel projection of a parallelogram onto a plane will still maintain that property. The resulting shape will have two pairs of parallel sides, making it a trapezoid. This is true for any type of parallel projection, including orthogonal projections where the projection lines are perpendicular to the plane of projection. So, to answer your question, a parallel projection of a parallelogram can indeed be a trapezoid.