An 8 by 19 ft wall has three 4 by 5ft windows. The area of three windows is what percent of the area of the entire wall

Area of the wall = 8 x 19 = 152 ft square
Area of the window = 4 x 5 = 20 ft square
Area of 3 windows = 20 x 3 = 60 ft square
The percent area of 3 windows from area of the wall = 60/152 or approximately .395 or 39.5%