Does Sterak's synergize with Trinity?
Sterak's increases base attack by 25% Does that mean it increases Trinity Force Spellblade damage since it is based on base attack?
Sterak's increases base attack by 25% Does that mean it increases Trinity Force Spellblade damage since it is based on base attack?
Yes
Yes, that's the concept of increasing "base ad" versus getting "bonus ad". Sterak increases your base ad and thus is the only item that boosts sheen procs.
In fact, if you're feeling crazy on aram, you can build a trinity and 5 sterak's on nasus or skarner. The additional base-ad from Sterak's Fury IS unique, but the base-ad from sterak's stats is NOT. Which means you can increase your base ad by 125% and then proc a trinity for roughly 500 bonus sheen damage. It's hilarious to see in action, and also counts to your max-crit statistics in post-game.
Synergizing with Triforce is pretty much the only thing it does.