A farmer has a cylindrical silo 15 m high and a radius of 4 m. How much paint would be required to paint the exterior of the silo if one liter of paint covers 10 ?I got this:2 x 3.14 x 16= 100.48 x 2 = 200.96 16 x 15= 240 240+200.96= 440.96m^2
No. First A typical gallon of paint covers ~ 200 sq ft. Maybe 400 ft? in an extreme case (USA units) 400 ft? ~ 9.03 m? a gallon is ~ 3.8 L 9.03 ÷ 3.8 ~ 2.4 m? ...There is NO WAY a Litre will cover 10 m?. Second A liter covers 10. ?? 10 WHAT, knucklehead ? 10 m? ? 10 silos? 10 people? 10 magic mushrooms? Third The top of a silo is rarely flat. Even indoor silos have some curvature to give the cylinder some additional strength. But if you want to assume the top is flat then its area is πr? not whatever you have (and I can't tell, since you didn't label your two expressions) Fourth A cylinder has the same area as a rectangle that you glue together (by two of its opposite edges). The area of a rectangle is l*w ; the length of a cylinder is its circumference which is 2πr so the surface area of a cylinder is 2πrh Fifth The farmer can't paint the bottom of the silo, duh.
We have to find the surface area of the silo. SA = area of cylinder + area of hemisphere = 2πrh + 2/3 (4πr^2) = 2π(4 m)(25 m) + 2/3 (4π)^2 m = 200π m^2 + 32/3 π m^3 = 210.6666......π m^2 ≈ 661.82885... m^2 I don't know how to reconcile surface area in m^2 with paint in L (or cc).
