Why did sloped armour make the Panther harder to destroy?

The Panther (Pz. V) tank utilized sloped armour specifically to increase its defensive effectiveness by causing incoming enemy shells to ricochet off the surface rather than penetrating the vehicle.1

By angling the armour plates, the tank effectively increased the amount of material a projectile had to pass through to achieve penetration, while simultaneously increasing the likelihood that a shell would deflect upon impact. This design feature was a direct response to the advanced capabilities of the Soviet T-34, which had successfully employed sloped armour to improve its own battlefield survivability.1