Santa Cruz Bottling is a manufacturer of organic soft drinks on the coast of central California. Its products are enjoying a growing reputation and increased demand throughout the American Southwest. Because of the high cost of transporting soft drinks, they are considering a new plant to serve the states of New Mexico and Arizona. A key concern in their search for a new location is the resultant transportation costs to serve their key markets. Following is a list of cities where their main wholesale customers are located, along with estimated annual demand in cases of product for each.

CITY	x-COORDINATES	y-COORDINATES	NUMBER OF CASES
Phoenix	245	245	25,000
Tucson	345	120	20,500
Albuquerque	795	445	28,500
Santa Fe	845	560	17,000

a. Use the centroid method to recommend a location for the new bottling plant.