Question

A square is a rectangle or a rectangle is a square?

Answer 1

Answer:

a square is also a rectangle.

So we include a square in the definition of a rectangle. (We don't say "Having all 90° angles makes it a rectangle except when all sides are equal then it is a square.")

Answer 2

Answer:

$\huge\tt\green{Hola \: ! }$

A square is a rectangle . ✓

A rectangle is a square . ✗