"So that area represents about (19.63 / 57.51 ) 34% of the total world landmass." 1/2 of said circle is ocean, not land. And some of said land is 'uninhabitabl

"So that area represents about (19.63 / 57.51 ) 34% of the total world landmass." 1/2 of said circle is ocean, not land. And some of said land is 'uninhabitable' i.e Gobi Desert. And Canada is 3.8 miles squared, implying that 3.5 of those are uninhabitable is rather off. By that calculation, you'd be excluding most of Quebec and Ontario, which are 'inhabitable' just sparsely populated, in which case much of Tibet and China would be comparably 'uninhabitable' as well.