First, I considered the selling prices of similar cars. The most relevant data point is the 2012 GMC Acadia V6 3.6L AT4 (AWD) (Mid) with 276000 km mileage, sold for 20000 SAR on 2024-07-21. This car is very similar in terms of variant and condition. Another relevant data point is the 2013 GMC Acadia V6 3.6L AT4 (AWD) (Mid) with 153000 km mileage, sold for 20500 SAR on 2024-05-06. Given the higher mileage of the target car, its value should be slightly lower. The listed prices for similar cars range from 19500 to 26500 SAR, but these are generally higher than actual selling prices. Considering the average condition and higher mileage of the target car, I estimate its market price to be slightly lower than the most similar sold car with 276000 km mileage.