Turkey is about 4 times bigger than South Dakota.

South Dakota is approximately 196,540 sq km, while Turkey is approximately 783,562 sq km, making Turkey 299% larger than South Dakota. Meanwhile, the population of South Dakota is ~814,180 people (82.2 million more people live in Turkey).
Tip: This to-scale comparison of South Dakota vs. Turkey uses the Mercator projection, which distorts the size of regions near the poles.