If I have combat armor, does it contribute anything while I'm in the power armor? I know it seems like a dumb question but I'm not sure.

I would assume so, the armour values of the PA is added to the values your regular gear provides in the apparel tab.

No, it does not. When you enter a power armor, anything you're wearing is ignored, and only PA parts' values are used.

My understanding is that nothing you're wearing applies while you are in Power Armor except the Power Armor itself.

Well, it's 2 to 1 in favor of regular armor having no affect inside PA which is good. I was hoping the answer was no so I could just not worry about regular body armor. Bethesda did a tiered armor system where the armors get stronger depending on the tier but there's no way to tell by name what tier a piece is if it has mods on it because it drops the initial identifier like "sturdy" in favor of the material mod like "enameled" so Sturdy Combat Armor Chest becomes Polymer Combat Armor Chest. The best you can do is guess which tier it is based on the amount of protection that it provides but the mods themselves change the protection so it's still tricky to tell. I hope some modder fixes that real soon. Just to make sure everyone knows what I mean, tier 1 combat armor arm pieces only cover the upper arm. Tier 2 has upper arm, elbow, and forearm pieces, and tier 3 has all of those plus a shoulder piece as well and the higher the tier, the higher the potential armor value. I like having a matching set of armor and was browsing an armor vendor and he has a bunch of metal armor that is better than my current combat armor but I can't tell if it's all the same tier and I don't want to buy it all up only to find out it doesn't match and I "can't" wear it. I could save first, but still. Bethesda really should have put some kind of identifier system in place to easily identify what tier a piece of armor is when looking at it in the loot or trade menus.

Higher tiers are named. For Combat Armor, the system is "Combat Armor" -> "Sturdy Combat Armor" -> "Heavy Combat Armor".

Well what about when you forgo wearing a Power Armor Helmet or say when a leg gives out?

See above, the identifier is dropped if the item already has a mod on it. Sturdy Combat Armor becomes Polymer Combat Armor so there's no name difference between the tiers if they have mods on them.

I notice that stat enhancing items like glasses also don't apply while you're in powered armor BTW.

That's dissapointing but understandable. At least there's always Graqe mentats.

I think it does, my power armor seems to have slightly more armor when im in it, but the power armor still makes up 95% of my armor stat

effects on your armour (like increased AP regen, time slowing down when at 20% life etc) still work when your in power armour

Is there anyplace you can see how many armor points you have?

According to the Guide, when you wear a PA Frame, all stats from gear is ignored and only PA parts are counted towards your total. So if your PA legs give say, 200 dmg res and one of them breaks, you just lose 200 dmg res. Same if you wear the helmet, you just voluntarily forego whatever amount of armor your helmet has.