Mr. Moore is building a wooden swing set for his two boys Melvin and Erick. Each supporting end of the swing set is to be an A-frame constructed with two 10 foot long 4-by-4s joined at a 45 degree angle. To prevent the swing set form tipping over, Clint wants to secure the base of each A-frame to concrete footings. How far apart should the footings for each A-frame be?