What safety precaution should you take while filling the fuel tank of a gasoline-powered boat?

I would think that first of all, there should be no smoking and no sparks since gasoline fumes are so explosive and if it is a metal nozzle and a metal filler pipe then perhaps the nozzle should be grounded to avoid sparks from static electricity from igniting the gas fumes. 

E. i hope it's you done your thing

Hypothesis: volumes of both figures are equal.the volume of  figure 1 is: .the volume of figure 2 is: .since , you can conclude that and . so, .volumes of figures are equal only when an angle in the basis is right (then figures will be the same), in another cases volume of figure 1 is less than volume of figure 2.the hypothesis was not correct in all cases.