Area of square in terms of side and diagonal

Find the ratio of area of square and area of square taking diagonal as side.

Diagonal of first square is half of the diagonal of the other, then the area of second square with respect to the area of the first square will be

The diameters of two circles are the side of a square and the diagonal of the square. The ratio of the areas of the smaller circle and the larger circle is

If the diagonals of a rhombus are 12 cm and 16 cm. Then, the area of square having its side equal to side of rhombus is