Question: The suburb east of Christie Downs has what land area?

full_context: Document 1: Division of Kingston: The Division of Kingston is an Australian Electoral Division in South Australia covering the outer southern suburbs of Adelaide. The 171 km² seat stretches from Hallett Cove and O'Halloran Hill in the north to Sellicks Beach in the south, including the suburbs of Aldinga Beach, Christie Downs, Christies Beach, Hackham, Hallett Cove, Huntfield Heights, Lonsdale, Maslin Beach, Moana, Morphett Vale, Old Noarlunga, Onkaparinga Hills, Port Noarlunga, Reynella, Seaford, Sellicks Beach, Sheidow Park, Port Willunga, Trott Park, Woodcroft, and parts of Happy Valley and McLaren Flat.
Document 2: Morphett Vale, South Australia: Morphett Vale is a southern suburb of Adelaide, South Australia in the City of Onkaparinga. It is the largest suburb in the state, with a population of more than 23,000 and an area of 12.76 km², followed by Paralowie with nearly 10,000 fewer residents. There are approximately 1,000 businesses in Morphett Vale.
Document 3: Happy Valley, South Australia: Happy Valley is a metropolitan suburb of Adelaide, South Australia. It is located 20 km south of the Central Business District of Adelaide.
Document 4: City of Tea Tree Gully: The City of Tea Tree Gully is a local council in the Australian state of South Australia, in the outer north-eastern suburbs of Adelaide. The city has an estimated population of 98,861 people and is one of the most populous local government divisions in Adelaide. The major business district in the city is at Modbury, where Tea Tree Plaza, the Civic Centre and the library are located.
Document 5: Port Noarlunga, South Australia: Port Noarlunga is a suburb in the City of Onkaparinga, South Australia. It is a small sea-side suburb, population 2,632, about 30 km to the south of the Adelaide city centre and was originally created as a sea port. This area is now popular as a holiday destination or for permanent residents wishing to commute to Adelaide or work locally. There is a jetty that connects to a 1.6 km long natural reef that is exposed at low tide. The beach is large and very long and has reasonable surfing in the South Port area whose name is taken from its location - 'South of the Port'.
Document 6: Christie Downs, South Australia: Christie Downs is a suburb in southern Metropolitan Adelaide within the City of Onkaparinga, South Australia. It has a unique postcode of 5164, and is adjacent to the suburbs of Christies Beach to the west, Noarlunga Centre to the south, Morphett Vale to the east and Lonsdale to the north.
Document 7: Port Noarlunga South, South Australia: Port Noarlunga South is a suburb in the Australian state of South Australia located in the Adelaide metropolitan area on the coastline of Gulf St Vincent about 30 km south of the state capital of Adelaide.
Document 8: Woodville West, South Australia: Woodville West is a suburb of Adelaide, situated about 9 kilometres northwest of the Central Business District. It lies within the City of Charles Sturt. The postcode of Woodville West is 5011. Woodville West is bounded by the railway line and Port Road in the north, Findon Road in the east, Trimmer Parade, Todville Street and Minns Street East in the south, and Frank Mitchell Park, Agnes Street and the railway line in the west. As of 2011, Renewal SA and the City of Charles Sturt have been implementing the Woodville West Neighbourhood Renewal Project, which involves an $130m property development.
Document 9: Glenunga, South Australia: Glenunga is a small southern suburb of 2,539 people in the South Australian city of Adelaide. It is located five kilometres southeast of the Adelaide city centre. The name Glenunga is taken from an Aboriginal language "unga" meaning near and "glen" because of its proximity to Glen Osmond (see Manning's places of South Australia by Geoffrey H. Manning published in 1990). Bounded on the north by Windsor Road, the east by Portrush Road, the south-west by Glen Osmond Road and the west by Conyngham Street, the leafy suburb forms a rough triangular layout. It is close by to other Burnside council suburbs of Toorak Gardens and Glenside.
Document 10: Noarlunga Centre, South Australia: Noarlunga Centre is a suburb in the City of Onkaparinga in the southern suburbs of Adelaide, South Australia. The suburb is mostly commercial, being dominated by the Centro Colonnades shopping centre and the small 'Inspire Noarlunga' estate to the east of Goldsmith Road. The suburb is bordered by Beach Road to the north, Dyson Road to the west Goldsmith Road to the south and the Southern Expressway to the east. Burgess Drive, Seaman Road and David Witton Drive are the main thoroughfares inside the boundaries of the suburb.
Document 11: Christie Downs railway station: Christie Downs railway station is located on the Seaford line. Situated in the southern Adelaide suburb of Christie Downs, it is 28.9 kilometres from Adelaide station.
Document 12: City of Onkaparinga: The City of Onkaparinga is a local government area (LGA) located on the southern fringe of Adelaide, South Australia. It is named after the Onkaparinga River, whose name comes from "Ngangkiparinga", a Kaurna word meaning women's river. It is the largest LGA in South Australia, with an estimated population of 164,800 people in both urban and rural communities and is also geographically expansive, encompassing an area of 518.3 km². The council is headquartered in the Noarlunga Centre with area offices situated in Aberfoyle Park, Woodcroft and Willunga.
Document 13: Onkaparinga Hills, South Australia: Onkaparinga Hills is a southern suburb of Adelaide, in the City of Onkaparinga. It covers an area of approximately 22 km2 . It has a population of 2534 people (2011 Census). It is a leafy suburb that includes parts of the Onkaparinga River National Park.
Document 14: Mount Osmond, South Australia: Mount Osmond is a small suburb of 2,497 people in the South Australian capital city of Adelaide. It is part of the City of Burnside local government area and located in the foothills of the Adelaide Hills, five kilometres south east of the city centre. The suburb is high on the hill of the same name, which is the last hill on the right when approaching Adelaide down the South Eastern Freeway before the road levels out onto the Adelaide Plains. It is bounded to the north by the suburb of Beaumont, to the north-east by Burnside, to the east by Waterfall Gully, to the south by Leawood Gardens/Eagle On The Hill, to the south-west by Urrbrae, to the west by Glen Osmond and to the north-west by St Georges.
Document 15: City of Onkaparinga: The City of Onkaparinga is a local government area (LGA) located on the southern fringe of Adelaide, South Australia. It is named after the Onkaparinga River, whose name comes from "Ngangkiparinga", a Kaurna word meaning women's river. It is the largest LGA in South Australia, with an estimated population of 164,800 people in both urban and rural communities and is also geographically expansive, encompassing an area of 518.3 km². The council is headquartered in the Noarlunga Centre with area offices situated in Aberfoyle Park, Woodcroft and Willunga.
ground_truth: 12.76 km²