To find the total area available for printing, we need to subtract the margins from the total area of the book.

The total area of the book is given by the product of its length and width: Total area = 20 cm * 14 cm = 280 cm^2

The margins on the short sides are 2.5 cm deep, so the effective length of the book is reduced by 2 * 2.5 cm = 5 cm. The effective length of the book is 14 cm - 5 cm = 9 cm.

The margins on the long sides are 2 cm deep, so the effective width of the book is reduced by 2 * 2 cm = 4 cm. The effective width of the book is 20 cm - 4 cm = 16 cm.

The total area available for printing is the product of the effective length and width: Total area available for printing = 9 cm * 16 cm = 144 cm^2

To find the area of each page, we divide the total area available for printing by the number of pages: Area of each page = Total area available for printing / Number of pages Area of each page = 144 cm^2 / 360 = 0.4 cm^2