The gods have given up on the habital planet scheme and have decided to design this universe differently. They have filled it with a space structure called a banks orbital. These habitats are purpose-built space habitat forming a ring many miles in diameter. The rotation of the ring simulates both gravity and a day-night cycle comparable to a planetary body orbiting a star.
These rings are massive, having the planet surface of 25 earths. Its inhabitants live on the inside of the ring, where continent-sized "plates" have been shaped to provide all sorts biomes. Many exist, such as deserts, jungles, etc. The natural environment and climate are similar to Earth, only covering a larger area.
I want a way to determine how many people can live on these massive rings in total without it becoming overcrowded enough to cause an issue. Our world has about 7 billion people, so I determined that I should multiply that by 25. However, this sounds stupid.
What can I do to find this answer?