The corresponding sides of two similar rectangles are 6 ft and 10 ft. The area of the smaller rectangle is 78 ft2. To the nearest whole number, what is the area of the larger rectangle?

We know one side of the smaller rectangle, 6ft. Therefore the longer side is 78/6 ft = 13ft.

The ratio of small to large side is 6:10, so the larger rectangles other length is (13 / 6) * 10 ft = 21.666 ... ft.

Thus the area of the larger rectangle is 21.666 ... * 10 = 216.666 ... ft^2, and hence to the nearest whole number it is 217 ft^2