Use differentials2 estim8 the amount of paint needed2apply a coat of paint .05 cm thick to a hemisphere. d=50m

My main question is would i use the surface area formula? 3 pi r^2? or would i use the Volume formula or the area formula.Use differentials2 estim8 the amount of paint needed2apply a coat of paint .05 cm thick to a hemisphere. d=50m
The Surface Area formula for a sphere is 4 pi r^2 so a hemisphere would be of course half of that. Given the diameter of 50 M into the formula:





2 pi (50/2)^2 = 2 pi (25)^2





1250pi m^2 = 12,500,000 pi cm^2





39,269,908 cm^2 * .05 cm = 1,963,495 cm^3





5,186 gallons