Given: Dimensions of red tiles and yellow tiles are 4 cm × 4 cm and 1 cm × 1 cm. There are 61 red tiles Formula used: Area of the square = Side2 Area of the diagonal = a√2, where a = side Calculation: According to the question, If there are 61 red tiles diagonally then there will 1 red tile in centre and other 60 tiles will be arranged in such a way as drawn in photo. ⇒ Diagonal of each red tile = 4√2 = 4√2 Diagonal of the square ABCD = Diagonal of one tile × no. of one tile ⇒ 4√2 × (15 + 15 + 1) = 124√2 cm Area of square= (diagonal2)/2 = (124√2)2/2 = 15336 cm2 Area of each red tile = 4 × 4 = 16 Area of 61 red tiles = 16 × 61 = 976 Area of 61 yellow tiles = 15376 - 976 = 14400 Area of each red tile = 1 × 1 = 1 Number of yellow tiles= 14400/1 = 14400 ∴ The number of yellow tiles are 14400.