Question: Who was the individual who is credited with establishing the size of earth?
Answer: Eratosthenes
Disambiguated annotations:
qaPairs: question: Who was the individual who is credited with establishing the size of earth around 240 BC?
answer: Eratosthenes of Cyrene
Eratosthenes
question: Who was the individual who is credited with establishing the size of earth  during the middle ages?
answer: al-Biruni
Abū Rayḥān Muḥammad ibn Aḥmad Al-Bīrūnī
Biruni
question: Who was the individual who is credited with establishing the size of earth using the star Canopus?
answer: Posidonius
question: Who was the individual who is credited with establishing the size of earth by adding to Eratosthene's estimate?
answer: Hipparchus
Hipparchus of Nicaea