Brahmagupta (598–668 CE) was an Indian mathematician and astronomer who wrote many important works on mathematics and astronomy.His famous work was Bhramasphuta-siddhanta.Its 25 chapters contain several unprecedented mathematical results.
Brahmagupta's Formula:
So that the approximate value of the area of this cyclic quadrilateral will be 
letting it 
the exact value of the area is 
Statement:
The approximate area is the product of the halves of the sums of the sides and opposite sides of a triangle and a quadrilateral. The accurate [area] is the square root from the product of the halves of the sums of the sides diminished by [each] side of the quadrilateral
Brahmagupta's Formula:
letting it the exact value of the area is Statement:
The approximate area is the product of the halves of the sums of the sides and opposite sides of a triangle and a quadrilateral. The accurate [area] is the square root from the product of the halves of the sums of the sides diminished by [each] side of the quadrilateral
