Change 2.99792478x10^8 into 3 significant figures

Change 2.99792478x10^8 into 3 significant figures

\(2.99792478\times 10^8\ m/s \ (speed \ of \ light)\) 

\(\times \frac{3600s}{h}\times\frac{km}{1000m}=1079252920.8\ km/h \)

\(\times \frac{mile}{1609.344\ m}=186282.409 \ mile/s \)

\(\times \frac{mile}{1609.344\ m}\times \frac{3600s}{h}=670616674.124 \ miles/h\)

\(\times \frac{mile}{1609.344\ m}\times \frac{60s}{min}=11176944.5687 \ miles/min\)

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2.99792478x10^8m/s is 3.00x10^8m/s to 3 significant figures

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