Finding an exact answer would be extremely difficult due to the Earth constantly moving closer or away from the sun all the time. Only Neil Degrasse Tyson would know for sure! XD
But, as of now, the Earth is 92.96 million miles from the sun:
1) Set up a proportion
1 cm x cm
------------------ = ----------------
92,960,000 mi. 5.056 x 10^13 mi.
2) cross multiply
5.056 x 10^13 = 92,960,000x
3) Divide both sides
5.056 x 10^13
-------------------- = x
92,960,000
x = 543889.845095 cm from the sun! :D
hope this helps..