text: Function to find distance
code: function distance ( a1 , b1 , c1 , d1 , a2 , b2 , c2 , d2 ) { let x1 , y1 , z1 , d ; if ( a1 / a2 == b1 / b2 && b1 / b2 == c1 / c2 ) { x1 = y1 = 0 ; z1 = - d1 / c1 ; d = Math . abs ( ( c2 * z1 + d2 ) ) / ( Math . sqrt ( a2 * a2 + b2 * b2 + c2 * c2 ) ) ; document . write ( " " + d ) ; } else document . write ( " " ) ; }