Below is an context that describes a sql query, paired with an question that provides further information. Write an answer that appropriately completes the request.  # noqa: E501
### Context:
CREATE TABLE table_16799784_7 (diameter__km_ VARCHAR, latitude VARCHAR)
### Question:
what is the diameter (km) of feature of latitude 40.5s
### Answer:
SELECT diameter__km_ FROM table_16799784_7 WHERE latitude = "40.5S"