Length of the direct common tangent between two externally touching circles | Function to find the length of the direct common tangent ; Driver code
function lengtang ( r1 , r2 ) { document . write ( " " + " " + ( 2 * Math . sqrt ( r1 * r2 ) ) . toFixed ( 5 ) ) ; } var r1 = 5 , r2 = 9 ; lengtang ( r1 , r2 ) ;