Playboy playmate are casted for their feminine body. I can't show nudity on this site, but Kerri Kendal is super feminine, with large breasts and voluptuous body.

Her jaw is almost a perfect square. A grade jaw angle and chin. There is no debate about that.
Look at her jawline. This is a perfect example of the ruler straight jawline.

Look at the flat under jaw plane. Skin is super tighten because of the jaw bone development.
I love these kind of triangular jaw planes resulting of a well developed mandible.