A trapezoid is a quadrilateral with 1 set of parallel sides.

A parallelogram is a quadrilateral with 2 sets of parallel sides.

A rectangle is a parallelogram with 4 right angles.

A square is a rectangle with 4 equal sides.

A rhombus is a parallelogram with 4 equal sides.

**Parallel lines** are lines which do not intersect.

**Perpendicular lines** are lines which intersect at right angles.

Trapezoids have 1 set of parallel sides.

Trapezoids can have right angles, and, therefore, perpendicular sides.

So, the quadrilateral could be a trapezoid.

Parallelograms have parallel sides.

Parallelograms have perpendicular sides when they are rectangles.

So, if it is a rectangle, the quadrilateral could be a parallelogram.

Similarly, if it is a square, the quadrilateral could be a parallelogram.

A rhombus has parallel sides.

A rhombus has perpendicular sides when it is a square.

So, if it is a square, the quadrilateral could be a rhombus.