[ 24/May/21 ]
If the questioner means Rhode Island (the US state), then it has an area just over 3,100km sq (3.1 x 10^9m^2). People come in many different sizes, but most are smaller than the average US citizen, so the average largest cross sectional area of a person is somewhat less than half a square meter. So everyone on the planet would be able to stand in Rhode Island, with a little bit of breathing room, but it would be a squeeze if everyone decided to lie down.
California is 140 times the size of Rhode Island. Everyone could actually live in California, if they were vegan, and if the best agricultural practices were followed. Wouldn’t be a lot of room to move around outside, and all the roofs would be growing stuff, and it is doable.