Explanation:

2πr = 4a where, r = radius of circle & a =side of square
or, πr = 2a
Given, area of the circle = 154 cm2,
πr² = 154
or, r =7 cm
Now, πr = 2a
or, 22*7/7 = 2a
or, a = 11 cm
So, area of the square= a²= 11² =121 cm²