Well, you can approximate -- Area of a sphere is 4πR2 Find the radius of your round object, square it, then multiply by 4(3.14159) = ~ 12.566... That is your area in units squared. Because it will wrap around the 'equator' of your object the Length will be the circumference at the equator. the circumference, which is C = πD (π * 2R). That will form your length. the Height of the paper will be 1/4 of a rotation (from the equator to the pole) to find how high each piece will need to be. Circumference / 4 = height. See image (you may need to view 'large' or 'original'