Question 11
Two overlapping squares with parallel sides are such that the part common to both squares has an area of $4\,\mathrm{cm}^2$. This is $\frac{1}{9}$ the area of the larger square and $\frac{1}{4}$ of the area of the smaller square. What is the minimum perimeter, in cm, of the eight-sided figure formed by the overlapping squares?