Problema Solution
A building is hemispherical in shape if the contractor used 20 gallons of paint for the floor, how many gallons of paint does he need to paint the exterior?
Answer provided by our tutors
the area of base of hemi-sphere is ( pi * r^2 ) which requires 20 gallons of paint.
the surface area of hemi-sphere is 2*pi*r^2. that is double the base area so total paint needed for surface = 2*20 = 40 gallons