what is the radius of the diameter 520 cm?

︎︎ ︎ ︎︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎︎ ︎ ︎︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎︎ ︎ ︎︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎︎ ︎ ︎︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎︎ ︎ ︎︎ ︎ ︎ ︎ ︎ ︎ ︎︎ ︎ ︎ ︎︎ ︎ ︎︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎︎ ︎ ︎︎ ︎︎︎ ︎ ︎︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎︎ ︎ ︎︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎︎ ︎ ︎︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎︎ ︎ ︎︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎︎ ︎ ︎︎ ︎ ︎ ︎ ︎ ︎ ︎︎ ︎ ︎ ︎︎ ︎ ︎︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎︎ ︎ ︎︎ ︎︎︎ ︎ ︎︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎︎ ︎ ︎︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎︎ ︎ ︎︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎︎ ︎ ︎︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎︎ ︎ ︎︎ ︎ ︎ ︎ ︎ ︎ ︎︎ ︎ ︎ ︎︎ ︎ ︎︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎︎ ︎ ︎︎ ︎︎︎ ︎ ︎︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎︎ ︎ ︎︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎︎ ︎ ︎︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎︎ ︎ ︎︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎︎ ︎ ︎︎ ︎ ︎ ︎ ︎ ︎ ︎︎ ︎ ︎ ︎︎ ︎ ︎︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎︎ ︎ ︎︎ ︎