This is the formula you would use to calculate how many tiles you would need.
# of tiles you need = Total square footage ÷ square footage of each tile
Total square footage: 69x69 = 4761 square feet
Square footage of each tile = 2x2 = 4 square feet
# of tiles you need = 4761 ÷ 4 = 1190.25
You will need 1190.25 tiles.