The solution is where the red line crosses the blue line, which on the X axis is between the 1 and the 2, so about 1.5.
Convert the fractions to decimal and see which one is close to 1.5:
13/8 = 1.625
25/16 = 1.5625
7/4 = 1.75
27/16 = 1.6875
The closest one to 1.5 is 25/16
The answer would be -10/20 which is simplified to -1/2
The first square has side lengths of 4 units(because the square root of 16 is 4). The second square has side lengths of 8 units. The third square has side lengths of 12 units. As you can tell, the side lengths increase by 4. So the fourth square will have side lengths of 16 units, and the fifth square will have side lengths of 20 units. The question wants the perimeter, so the answer is 20*4(sum of 4 sides of equal lengths) which is 80 units.
($3.91)(0.09) = $0.3519
$3.91 + 0.3519 = $4.2619 per gallon
if you're looking for the total expense next year:
($4.2619)(370 gallons) = $1,576.903
