The following tutorial provides an example of a 3x3 matrix request with the following origins and destinations:
San Francisco at (37.76, -122.42)
New York at (40.63, -74.09)
Austin at (30.26, -97.74)
To calculate a car distance matrix, you can use the request below. Since the request does not specify a destinations array, the origins are taken as destinations and the resulting matrix is a 3 x 3 matrix. The region definition is the special variant world. By default, the service calculates a travel times matrix, but since we want to get distances in the response instead of times, the request specifies the matrixAttributes property with the value distances.