Who was the individual who is credited with establishing the size of earth?
The first published reference to the Earth's size appeared around 350 BC, when Aristotle reported in his book "On the Heavens" that mathematicians had guessed the circumference of the Earth to be 400,000 stadia. Scholars have interpreted Aristotle's figure to be anywhere from highly accurate to almost double the true value. The first known scientific measurement and calculation of the circumference of the Earth was performed by Eratosthenes in about 240 BC. Estimates of the accuracy of Eratosthenes's measurement range from 0.5% to 17%. For both Aristotle and Eratosthenes, uncertainty in the accuracy of their estimates is due to modern uncertainty over which stadion length they meant.
Who was the individual who is credited with establishing the size of earth around 240 BC?
Eratosthenes of Cyrene Eratosthenes
Earth radius
No context provided
Who was the individual who is credited with establishing the size of earth  during the middle ages?
al-Biruni Abū Rayḥān Muḥammad ibn Aḥmad Al-Bīrūnī Biruni
No context provided
Who was the individual who is credited with establishing the size of earth using the star Canopus?
Posidonius
No context provided
Who was the individual who is credited with establishing the size of earth by adding to Eratosthene's estimate?
Hipparchus Hipparchus of Nicaea
McKinsey & Company
https://en.wikipedia.org/wiki/McKinsey%20%26%20Company
Earth radius
https://en.wikipedia.org/wiki/Earth%20radius
Earth
https://en.wikipedia.org/wiki/Earth
Hipparchus apparently made many detailed corrections to the locations and distances mentioned by Eratosthenes.
Hipparchus Astronomical instruments and astrometry
The first known scientific measurement and calculation of the circumference of the Earth was performed by Eratosthenes in about 240 BC. Hipparchus made many detailed corrections to the locations and distances mentioned by Eratosthenes and added to his estimate. Abū Rayḥān Muḥammad ibn Aḥmad Al-Bīrūnī established the size of the Earth during the Middle Ages. Posidonius established the size of Earth using the star Canopus.