Widen Area [one-action] Feat 4

You set up your area weapon to affect more targets. If the next action you use is to Area Fire or Auto-Fire in a burst, cone, or line, or if you use Whirling Swipe, you increase the area of that attack. Add 5 feet to the radius of a burst that normally has a radius of at least 10 feet (a burst with a smaller radius isn’t affected). Add 5 feet to the length of a cone or line that’s normally 15 feet or smaller, and add 10 feet to the length of a larger cone or line.