Apologies for the delay. Yesterday and so far today I've been lecturing on the operation of anesthesia machines. Stuff that would put you guys to sleep.
So Bill has the right idea about using Follow Me. if you wanted to do a thing with a cone shaped hole, you would draw the section of the part with the triangle missing. For something that is round like that, you could draw a section of the entire thing and use Follow Me in one operation.
Using cardinal points to do the resizing can also be useful although I would probably lean toward the Follow Me method because it would be easier to be precise about the angles and radii of the part.
By the way, in Bill's illustration of the cone made with Follow Me, it ends up without a base. If you want the base to be drawn in, either delete the face of the circle of draw the circle so it is not in contact with the profile. And correct the face orientation after you've completed the Follow Me operation.
Irony: The opposite of Wrinkly