Every Panther produced had the same layout, 8 cm upper hull at 35 degrees (from horizontal, 55 from vertical), lower hull 6 cm with the same slope.
In a normal tank engagement on flat terrain you can't hit the lower hull, you need a projectile flying strait to this area but no other tank/afv fires from a position low enough to hit it reliably and with sufficient penetration power. That's why I mentioned a Panther exposing its belly (hull in upwards angle).