Tanzania is about 350 times bigger than Rhode Island.

Rhode Island is approximately 2,706 sq km, while Tanzania is approximately 947,300 sq km, making Tanzania 34,907% larger than Rhode Island. Meanwhile, the population of Rhode Island is ~1.1 million people (62.8 million more people live in Tanzania).
Tip: This to-scale comparison of Rhode Island vs. Tanzania uses the Mercator projection, which distorts the size of regions near the poles.