Step by Step: First we find how many feet is needed to go around 1 window. We do this by adding up all four of its sides. 4+4+2+2= 12 Because there are 15 windows be multiply the feet needed for 1 window by 15. 12•15=180 Repeat the first two steps for the garage doors to find that she needs 108ft of lights for 3 garage doors and add the feet needed for the windows to the feet needed for the garages 180+108=288