The problem statement suggests you should convert dimensions to inches to work this problem. .. 2.75 ft = 33 in .. 1.5 ft = 18 in The empty height is .. 0.6*7 in = 4.2 in so the empty volume is .. V = (33 in)*(18 in)*(4.2 in) = 2494.8 in³
Multiplying this by the conversion factor to gallons gives .. V = (2494.8 in)³ × (1 gal)/(231 in³) = 10.8 gal
It will take 10.8 gallons of gas to fill the tank.
The obvious answer is 6. If three of the lengths are 6, and there are four total sides, then you would need 6 to complete the shape, as it is a square, and a square is a type of trapezoid.
