How is the physical radius of stars like Betelgeuse often expressed for comparison?

Relative to the Sun's radius (solar radii, R extsubscript{odot})

While determining the true physical diameter of a star requires knowing its precise distance along with its observed angular size, stating the radius in absolute kilometers often results in numbers too large and difficult to interpret instantly. Therefore, astronomers commonly express stellar radii relative to a known benchmark: the radius of our Sun, denoted as solar radii ($R_ ext{odot}$). For instance, the red supergiant Betelgeuse is estimated to possess a radius about $900$ times that of the Sun ($900 ext{ R}_ ext{odot}$). This practice simplifies comparative astronomy immensely, allowing immediate visualization of scale—a star listed at $5 ext{ R}_ ext{odot}$ is instantly understood to be substantially larger than the Sun, without needing to process a massive kilometer value.