Okay. fist off don't think of them as 5 units each, but 1. so if you were to put it on graphing paper and box squares each time. you would be able to get 8 in for both sides to make a square. Area then would be 1600ft squared because 8 ×5 is 40 and 40×40 is 1600. then you calculate how many squares you used. 8×8=64. and 80-64=16 so 16 pieces are left over. then 9×9 (increasing the square) is 81. so 17 pieces to increase it.
£480
2:3:7 = 2+3+7 = 12
2
--- 0f £480 = £80
12
3
--- of £480 = £120
12
7
--- of £480 = £280
12
answer = £80 : £120 : £280
9 * 3/4 = 6.75
You could change 3/4 into a decimal by dividing 3 by 4, which equals ,75.
Four and seven thousand sixty-five hundred thousandths, I believe