Quadrilaterals are plane (2-D) shapes. They are bounded by four straight sides. They have four vertices and the sum of the internal angles at these vertices add to 360 degrees.
They are quadrilaterals; opposite sides are parallel.
Not all quadrilaterals are rectangles. Some quadrilaterals are rectangles, and the rest are not. However, all rectangles are quadrilaterals.
All rectangles are quadrilaterals. A quadrilateral has 4 sides; all rectangles have 4 sides; thus all rectangles are quadrilaterals.
They are both quadrilaterals.
Rhombuses and Rectangles