No, not all parallelograms are rectangles. A parallelogram is a quadrilateral with opposite sides that are parallel and equal in length, while a rectangle is a special type of parallelogram where all angles are right angles.
To explain further, a rectangle meets the criteria of a parallelogram but adds an additional requirement: every angle must be 90 degrees. A square is another specific type of rectangle where all sides are also equal in length.
In summary, while all rectangles are parallelograms, not all parallelograms can be classified as rectangles because they don’t necessarily have right angles. To visualize, consider a rhombus—a type of parallelogram with equal side lengths but not right angles. This exemplifies how a parallelogram can exist without being a rectangle.