Just learning AutoCAD. I don’t understand how to change the length of a Polyline segment to an exact value. The attached file illustrates. I can do it with PEDIT but it takes a long sequence of steps. Isn’t there a way of doing it directly?

(I'm running AutoCAD LT 2020 on a Mac but I thought this probably works the same in all editions to I'm posting to the AutoCAD forum. If that's not so, please tell me which forum to move this to. Thanks.)