If the shape of the room is a square, then the square root of the sum of the squares of the the two adjacent sides will give the diagonal.
i.e.
Since the square root of the sum of the squares of the the two adjacent sides is 24.04 and not 18.79, therefore, the shape of the room is not a square.
i.e.
Since the square root of the sum of the squares of the the two adjacent sides is 24.04 and not 18.79, therefore, the shape of the room is not a square.