SB 5.21.1
sri-suka uvaca
etavan eva bhu-valayasya sannivesah pramana-laksanato vyakhyatah.
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
Sukadeva Gosvami said: My dear King, I have thus far described the diameter of the universe [fifty crores of yojanas, or four billion miles] and its general characteristics, according to the estimations of learned scholars.