So a square is a special kind of rectangle, it is one where all the sides have the same length. Thus every square is a rectangle because it is a quadrilateral with all four angles right angles. However not every rectangle is a square, to be a square its sides must have the same length.
How I got my answer is that you write the numbers and the difference of the each 2 numbers. When you see the pattern is 5, 10, 20, and it might as well be 25 because you are going to start all over with the pattern