For Stellenbosch, which has a population larger than 155,733, what is the average area?
CREATE TABLE table_42838 (
    "Name" text,
    "Seat" text,
    "Population (2011)" real,
    "Area (km 2 )" real,
    "Density (inhabitants/km 2 )" real
)
SELECT AVG("Area (km 2 )") FROM table_42838 WHERE "Name" = 'stellenbosch' AND "Population (2011)" > '155,733'
Below are sql tables schemas paired with instruction that describes a task. Using valid SQLite, write a response that appropriately completes the request for the provided tables. ### Instruction: For Stellenbosch, which has a population larger than 155,733, what is the average area? ### Input: CREATE TABLE table_42838 (
    "Name" text,
    "Seat" text,
    "Population (2011)" real,
    "Area (km 2 )" real,
    "Density (inhabitants/km 2 )" real
) ### Response: SELECT AVG("Area (km 2 )") FROM table_42838 WHERE "Name" = 'stellenbosch' AND "Population (2011)" > '155,733'