We can use ratios here. The real size would have to be proportional, meaning that if I increase the line on the drawing 5 times, the real size would have to increase 5 times as well.
We can obviously see, after having said that, that the real window would have to be 35ft long (because we multiplied 1 inch by 5, and if 1 inch represents 7 feet, then we also have to multiply that by 5 so it’s proportional, and 7*5=35)
We can check too — 1 in : 7 ft = 5 in : x ft
x = (7ft * 5in) / 1in — we would get the same result :)
