Question 1195301
a hemisphere is half a sphere.
the base of the hemisphere is a circle.
the area of a circle is equal to pi * r^2.
r is the radius of the circle.
the surface area of a sphere is equal to 4 * pi * r^2.
the surface area of a hemisphere is equal to 2 * pi * r^2 (half the surface area of a sphere).
the ratio of the surface area of a hemisphere to the area of a circle is equal to 2 * pi * r^2 / pi * r^2 = 2 / 1.
if 40 liters of paint were required to paint the floor, then 80 liters of paint would be required to paint the exterior of the building.
this assumes the floor dimensions are to the exterior of the building rather than the interior, since the thickness of the building structure would need to be taken into consideration as well.
that's what i think is your solution.