From the information given,
length of side of the larger square = 5x units
The area of a square is calculated by the faormula,
area = length of side^2
Thus,
Area of larger square = (5x)^2 = 25x^2
The smaller square has an area equal to ⅑ of the larger square. This means that the area of the smaller square is
Area of smaller square = 1/9 * 25x^2 = 25x^2/9
Length of the side of square = square root of area
Thus,
Length of the sides of the smaller square = square root of (25x^2/9)
Length of the sides of the smaller square = 5x/3