Convert from block [East U.S.] to quadrant

Unit Definition (block [East U.S.])
The Block is an informal unit of distance popular in the U.S. A block is the average distance between street intersections in the rectangular street grids common in most American cities. The length of a block in Eastern USA is about 1/20 mile or 80 meters.

Unit Definition (quadrant)
The quadrant is a unit of distance equal to the distance from the North Pole to the Equator. The metric system was originally designed to make this distance exactly 10 million meters (6213.71 miles). The actual meter comes close to the design. Using the conventional figures of 12 756 kilometers for the equatorial diameter of the earth and 12 714 kilometers for the polar diameter, and assuming the earth to have elliptic cross section, the length of the quadrant is about 10 001 300 meters (6214.52 miles). In principle, the quadrant is divided into 5400 nautical miles; in fact, 5400 international nautical miles equal 10 000 800 meters.