step 1
Find out the surface area of the figure
The surface area of the cylinder (without the base and the top)
[tex]SA=2\pi rh[/tex]where
r=12 ft
h=50 ft
pi=3.14
substitute
SA=2(3.14)(12)(50)
SA=3,768 ft2
step 2
Find out the surface area of the hemisphere
SA=2pir^2 ------> surface area of hemisphere
we have
pi=3.14
r=12 ft
substitute
SA=2(3.14)(12^2)
SA=904.32 ft2
step 3
the total surface e area is
3,768+904.32=4,672.32 ft2
step 4
Find out the number of gallons
we have that
1 gallon -------> 224 ft2
so
applying proportion
4,672.32/224=20.85 gal
therefore