A super large cross-section rectangular pipe jacking machine is put into use in the construction of a subway station in Hangzhou, Zhejiang province, on Aug 26. [Photo/China News Service] A super large ...

The area of each square is 1 cm 2. There are 12 squares contained in this rectangle. The area of the rectangle is 12 cm 2. The area of a rectangle can also be calculated using the following formula.

You might think it would be a good idea to put the two sensors in the centers of the two rectangles. However, a large distance measurement (say, of 75 meters) yields an over-large rectangle to search.