Maximum area of quadrilateral | JavaScript program to find maximum are of a quadrilateral ; Calculating the semi - perimeter of the given quadrilateral ; Applying Brahmagupta 's formula to  get maximum area of quadrilateral ; Driver code
function maxArea ( a , b , c , d ) { let semiperimeter = ( a + b + c + d ) / 2 ; return Math . sqrt ( ( semiperimeter - a ) * ( semiperimeter - b ) * ( semiperimeter - c ) * ( semiperimeter - d ) ) ; } let a = 1 , b = 2 , c = 1 , d = 2 ; document . write ( maxArea ( a , b , c , d ) ) ;