What percentage is this of the earth's speed around the sun? assume that the orbit of the earth is a circle with the radius of 1.5⋅1011 m

< Assume that the orbit of the earth is a circle with the radius of 1.5⋅1011 m. *I need help on this one* > 

Distance the earth covers in one year = 2 * pi * radius. The speed is the distance / time. 

< 1.88*10^-6 > what are the units? 

Convert your time unit from 1 year to the same units. For example, if it's seconds, convert 1 year = seconds (3.16 * 10^7 seconds using 365 1/4 days per year). 

Calculate the distance the earth travels in one orbit divided by the time.