Then run home three home * * * and the running length is: 3*(2πr)+2r=(6π+2)r (1).

Xiao Gang ran away: 6:55-6:35=20 minutes.

Ran: 260.5 * 20 = 5210m (2)

According to (1) (2), (6π+2)r =52 10.

Solution: r=250 meters

So: the perimeter of the community is: 2π r = 2 * 3.14 * 250 =1570 meters.