getDist function

function getDist(firstObject:Object,secondObject:Object) {
            var distance:Number = Math.sqrt( ( firstObject.x - secondObject.x ) * ( firstObject.x - secondObject.x ) + ( firstObject.y - secondObject.y ) * ( firstObject.y - secondObject.y ) );
            return distance;
        }

// example
if(getDist(firstThing,secondThing) <= tooCloseRadius){
firstThing.move();
}