Resolution

ppi is not a magic figure. The required ppi reduces with viewing distance. Work out the viewing distance in inches then use the formula below.

ppi required = 6878/Viewing distance

As an approximation a 10ft x 10 ft poster is unlikely to be viewed closer than 10 feet (120inches). So that forumala works out as :

ppi required = 6878 / 120 = 57ppi

Using any higher resolution at a 10 foot viewing distance is wasted. Our eyes simply cannot resolve it. If you know the viewing distance will be different, then substitute it into the formula.

Dave

Being it is so large it is most likely for billboard or sign usage. I would recommend for the print world it should be 300dpi or 118.11 ppi to keep the best resolution.

Like c.pfaffenbicher said it really depends on the usage and your printer.

»dpi« are none of your business unless you are the actual print provider, you probably mean »ppi«. 

The necessary resolution depends on the intended (or likely) viewing distance, in a case like this I would expect 72ppi effective resolution to be plenty. 

http://www.northlight-images.co.uk/article_pages/print_viewing_distance.html

50 to 100 would be good. Check with their printer.