Add seam allowances outside these lines, and some extra to make a drawstring casing at the top. Cut two, sew the sides up, and fold down the top for the drawstring, and you get:
The difference between triangular insets (left) and a proper gore (right) seen from the front...
...and from the side.
Now you know why I get so excited about a waist seam!
The gore, not the rectangle, is the foundation for skirts in most of the 1500s. If you make it wider, so there’s extra fabric at the waist for pleating, you’d have something like this:
A gored skirt, on a doll. This one is gathered, rather than pleated, and worn without a support skirt or pads.
We’ve got folds that fall softly down the length, because the width of the skirt keeps increasing down it’s length, and even without a support skirt it takes a vaguely conic shape. Compare this to a skirt cut with a rectangular or circular plan:
Notice the difference in the fall of the gored skirt (left) and the rectangular skirt (right).
From the side, you can see that the gored skirt (left) is always a cone shape, while the rectangular skirt (right) wants to become more of a domed bell unless you take pains to smooth it down.
The gored skirt (left) does not have the extreme fullness about the hem that a circle skirt (right) does.
The gored skirt (left) and circle skirt (right) seen from the side. It just looks about the same, doesn't it?
Next: From Gore to Alcega, and Back…