Given that the area of a circle varies as the square of its radius... Complete School Algebra - Page 474 by Herbert Edwin Hawkes, William Arthur Luby, Frank Charles Touton - 1919 - 507 pages Full view - About this book
...till the returns are brought home: and this cost increases, though irregularly, with the distance. But the area of a circle varies as the square of its radius. Therefore improvements in the mechanism or the organization of transport, which increase the distance...