Explanation: ধরি, smaller square এর diagonal \(= d\). \(\therefore\) Larger square এর diagonal \(= 3d\). Area of a square \(=\frac{1}{2} \times (diagonal)^2\). Area of smaller square \(= \frac{1}{2}d^2\). Area of larger square \(= \frac{1}{2}(3d)^2 = \frac{1}{2} \times 9d^2\). Fraction of shaded area \(= \frac{\text{Area of smaller square}}{\text{Area of larger square}} = \frac{\frac{1}{2}d^2}{\frac{9}{2}d^2} = \frac{1}{9}\). Fraction of the area of the larger square not shaded \(= 1 - \frac{1}{9} = \frac{8}{9}\).