No, not all parallelograms are rectangles, but all rectangles are parallelograms.
A parallelogram is a four-sided figure (quadrilateral) with opposite sides that are parallel and equal in length. This definition includes various shapes such as rectangles, rhombuses, and squares. The key characteristic of a parallelogram is that its opposite angles are equal and the opposite sides are parallel.
A rectangle, on the other hand, is a specific type of parallelogram where all four angles are right angles (90 degrees). This means that while every rectangle fits the definition of a parallelogram, there are many parallelograms that do not have this property. For instance, a rhombus is also a type of parallelogram, but it has all sides of equal length and opposite angles that are equal but not necessarily right angles.
In summary, while rectangles are a subset of parallelograms, not all parallelograms are rectangles because they do not all meet the criteria of having right angles.