The Compendious Book on Calculation by Completion and Balancing

The Compendious Book on Calculation by Completion and Balancing (, al-Kitāb al-Mukhtaṣar fī Ḥisāb al-Jabr wal-Muqābalah; ), also known as Al-Jabr (), is a mathematical book on algebra written by  Muḥammad ibn Mūsā al-Khwārizmī around 820 CE. Al-Jabr was important in the history of mathematics, the term "algebra" itself derived from Al-Jabr.

 Area and volume 
The book show ways of finding area and volume. These include approximations of pi (π), as 3 1/7, √10, and 62832/20000. This latter approximation, this equals 3.1416, which appeared in Āryabhaṭīya (499 CE).B.L. van der Waerden, A History of Algebra: From al-Khwārizmī to Emmy Noether; Berlin: Springer-Verlag, 1985. 

References

Category:Mathematics books
Category:9th-century works
Category:Arabic literature