Talk:Nasus/@comment-24663301-20140630003448/@comment-15280970-20140727005402

1 - 100/(100 + 54.1) x 100% = 35.1% dmg reduction 

1 - 100/(100 + 54.1 - 19) x 100% = 26% dmg reduction 

35.1% - 26% = ~9% difference 

'''How do I explain... AD Nasus deals (100-35.1=  64.9%) physical damage to Vayne. Armorpen Nasus deals (100-26= 74%) physical damage to vayne. 74/64.9= 1.14 Multiplier, in other words a 14% increase in damage. 9% is the difference betweens reductions not between damages.'''

''The theory stands that Arpen would be better for Nasus simply because his Q can scale indefinitely whereas flat AD runes will only mean +15 AD from the start of the game until the end of time. ''

What I meant is that those 15 AD would get you more stacks (because AD increases your sustain and last hits against armorless early minions, and your kill potential; this means you get CDR and more farm that will increase your damage past that 14%).