Multiplying more than two rational numbers

I’m really confused and need your assist me with this question i’ve never been taught

A, at (-2, 4), is 6 .of a'? (-8, 4) (-8, -2) (-2, -2) (-2, 4) b, at (-4, -7), isy-.of b'? (-4, 7) (4, -7) (4, 7) (-4, -7)

The plant were you work has a cylindrical oil tank that is 2.5 feet across on the inside and 10 feet high. the depth of the oil in the tank is 2 feet. about how many gallons of oil are in the tank?