Rhode Island is about 73 times smaller than South Dakota.

South Dakota is approximately 196,540 sq km, while Rhode Island is approximately 2,706 sq km, making Rhode Island 1.38% the size of South Dakota. Meanwhile, the population of South Dakota is ~814,180 people (238,387 more people live in Rhode Island).
Tip: This to-scale comparison of South Dakota vs. Rhode Island uses the Mercator projection, which distorts the size of regions near the poles.