1 Gallon of paint covers 100 sq ft, how many gallons are needed to paint the outside of a sphere 10 ft diametr

The surface area of a sphere is 4pir^2.


Knowing the diameter we can find the radius.


The radius is 5.


4pi(5)^2=SA


4pi25=SA


100pi=SA


So the surface area of the sphere is 100pi.


Pi~3.14


The surface area is around 314


314/100=xgallons


3.14gallons to paint the sphere.


PiGallons is the exact answer.1 Gallon of paint covers 100 sq ft, how many gallons are needed to paint the outside of a sphere 10 ft diametr
Area of a sphere = 4 pi r^2





4*3.14*25 = 314 square feet





314 square feet * 1 gal/100 square feet = 3.14 gal





You need 3.14 gallons, but if you're buying in gallon cans, then you'll have to buy 4 gallons.1 Gallon of paint covers 100 sq ft, how many gallons are needed to paint the outside of a sphere 10 ft diametr
The surface area of a sphere is A = 4*pi*r^2,





The radius of a sphere is 1/2 its diameter. IN this case r = 10/2 = 5 ft.





So its surface area is 4* pi * 5^2 = 4 * pi * 25 = 100 * pi = 314.159265358979... sq. ft.





So if one gallon covers 100 sq ft, you'd need 3.14... gallons.





If you have to buy the paint in units of 1 gallon, then you'd need 4 gallons.
Try ';surface area of a sphere'; in a search engine
Ok this is how to do it:





Use sphere area formula: 4(pi)r^2 = A. So r = 5 here and thats A = 100pi which is about 314 sq ft. So it would be 3.14159 gallons of paint needed for this job.





You can do this w/o a calculator, it simple moving around decimals.
pi gallons, or 3.14 gallons