To estimate the price of the 2019 Mazda 6 I4 2.5L R (Mid) with 180178 km mileage, I considered several data points. First, I looked at the selling prices of similar cars. A 2017 Mazda 6 I4 2.5L R (Mid) with 90000 km sold for 31000 SAR on 2023-10-22, and a 2020 Mazda 6 I4 2.5L Ignite (Top) with 138000 km sold for 69000 SAR on 2024-06-12. Given the target car's higher mileage and average condition, its value should be lower than the 2020 model but higher than the 2017 model. Next, I reviewed listed prices of similar cars. A 2019 Mazda 6 I4 2.5L R (Mid) with the same mileage is listed for 55000 SAR, and a 2018 Mazda 6 I4 2.5L Signature (Top+) with 185000 km is listed for 55000 SAR. Considering the target car's average condition and higher mileage, its value should be slightly lower than these listings. Finally, I factored in depreciation and market trends to arrive at a fair estimate.