Brahmagupta · Mathematics

The Area of a Cyclic Quadrilateral

Brahmagupta’s celebrated formula for the area of a four-sided figure from its sides alone - the generalisation of Heron’s triangle formula - together with his deep results on cyclic quadrilaterals, and the subtle truth that the formula is exact only when the corners lie on a circle.

What you'll be able to recall

You learned Brahmagupta’s formula for the area of a cyclic quadrilateral from its four sides (the semiperimeter form that generalises Heron’s triangle formula), that it is exact only when the vertices lie on a circle, and that Brahmagupta also gave results on the diagonals and on rational ‘Brahmagupt…

Leads to Bhaskara II.

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