1 gallon = $3 so the ratio would be 1:3 where 1 would represent the gallon and 3 the price
X=3
x is the width of the sidewalk
The outside dimensions of the walkway are 12 + 2x by 8 + 2x
The total area is (12 + 2x)(8 + 2x)
The total area minus the area of the pool should be equal to the area of the pool
Hoped this helped!
The place value of a certain digit is 10 times bigger than its adjacent digit to the right so the compare to the 5 in the thousands place it is 1000 times bigger than the 5 in the ones place and 10 times bigger than the 5 in the hundreds place