South Dakota is about 1.5 times smaller than Philippines.

Philippines is approximately 300,000 sq km, while South Dakota is approximately 196,540 sq km, making South Dakota 65.51% the size of Philippines. Meanwhile, the population of Philippines is ~114.6 million people (113.8 million fewer people live in South Dakota).
Tip: This to-scale comparison of Philippines vs. South Dakota uses the Mercator projection, which distorts the size of regions near the poles.