Is square a rectangle? or rectangle is a square?
All squares are rectangles. Not all rectangles are squares.
A quadrilateral is a rectangle if all four internal angles are
A quadrilateral is a square if all four internal angles are
Note that the first condition for a square is the same as the only condition for a rectangle, and thus all squares are rectangles. However, there is no condition which requires a rectangle to have four equal sides, and thus not all rectangles are squares. For example:
The above is a rectangle, as all four angles are