Answer :
A cylinder tank has a radius of 7.5 feet and an altitude of 14 feet. If a gallon of paint will cover 130 ft.² of surface how much paint is needed to put two coats of paint on the entire surface of the tank?
Remember that
The surface area of a cylinder is equal to
[tex]SA=2B+Ph[/tex]where
B is the area of the circular nase
P is the circumference of the circular base
h is the height of the cylinder
so
Find out B
[tex]B=\pi\cdot r^2[/tex]we have
r=7.5 ft
pi=3.14
substitute
[tex]\begin{gathered} B=3.14\cdot(7.5)^2 \\ B=176.625\text{ ft2} \end{gathered}[/tex]Find out the circumference
[tex]\begin{gathered} P=2\pi\cdot r^{} \\ P=2(3.14)\cdot7.5 \\ P=47.1\text{ ft} \end{gathered}[/tex]the value of h=14 ft
therefore
SA=2(176.625)+47.1(14)
SA=1,012.65 ft2
Remember that s needed to put two coats of paint
Multiply the surface area by 2
1,012.65*2=2,025.3 ft2
1 gallon -------> 130 ft2
applying proportion
1/130=x/2,025.3
solve for x
x=2,025.3/130
x=15.6 gal
therefore
