Ideal chin throat angle is:
Neck–chin–angle
Cervicomental angle should be approximately 90 degrees. The angle is more obtuse in females as compared to males. The soft tissues sag in older individuals and contributes to less than ideal submental form.
Lip–chin–throat angle
The angle between the lower lip and deepest point along the neck chin contour should be approximately 90 degrees.
An obtuse angle is unaesthetic and more so as the angle increases. This often reflects:

Chin deficiency
Retropositioned mandible
Lower lip procumbency
Excessive submental fat
Low hyoid bone position
120o
70o
130o
90o