The Diagonals of two squares are in the ratio of 2:5. find the ratio of their areas.

Correct Answer : B.

Let the diagonals of the squares be 2x and 5x.
Then ratio of their areas will be
                         $$\begin{gathered} Area of square=\frac{1}{2} * Diagona{l}^2 \\ \frac{1}{2} * 2x^2 : \frac{1}{2} * 5x^2 \\ 4x^2 : 25x^2 = 4 : 25 \end{gathered}$$