Answer
a) $510227657.736 km^{2}$
b) $510.227657736 Mm^{2}$
c) $5.102276577^{16} dm^{2}$
Work Step by Step
a) Using the conversion factor of $1mi^{2}=2.59 km^{2}$, we simply multiply the square miles by 2.59; $197000000 mi^{2}×2.59= 510227657.736 km^{2}$
b) Using the conversion factor of $1mi^{2}=2.59^{-6} Mm^{2}$, we simply divide the square miles by 386102.159
; $197000000 mi^{2}\div 386102.159= 510.227657736 Mm^{2}$
c) Using the conversion factor of $1mi^{2}=2.59^{8} dm^{2}$, we simply multiply the square miles by $2.59^{8}$
; $197000000 mi^{2}\times 2.59^{8}=5.102276577^{16} dm^{2}$