Question

All rectangles are parallelograms but all parallelograms are not rectangles justify this statement

Answer 1

the main characteristic of a parallelogram is that the opposite sides must be parallel to each other .
In a rectangle the opposite sides are parallel to one another . Therefore it is a parallelogram.

Now the main characteristic for a rectangle is that the opposite sides must be equal and all the angles must be 90 degrees .
A parallelogram has opposite equal sides but the angles may not be 90 degrees .
Therefore all parallelograms cannot be rectangles .