Question 865807
Let z = height in feet


3 ft. 9 in. is 3.75 feet.
volume is {{{3.75*3.75*z(ft*ft*ft)=400*gallons(1*ft^3/(7.48*gallons))}}}
{{{highlight_green((3.75)^2*z=400/7.48)}}}
Solve for z.