power attack w/OA or Reaping Strike

[mrcatman]

Can you use the power attack feat with a basic attack (or opportunity attack)?

Can you use power attack with reaping strike, such that on a miss, you get the extra power attack feat damage added to the normal "half strength modifier damage" of that power's miss?

Thanks ahead of time!

 

[Kordeth]

Can you use the power attack feat with a basic attack (or opportunity attack)?

Yes. Power attack says "when making a melee attack."

Can you use power attack with reaping strike, such that on a miss, you get the extra power attack feat damage added to the normal "half strength modifier damage" of that power's miss?

You can use Power Attack with reaping strike, but the damage will only be added on a hit. Power Attack plainly says when you hit with the attack, you get a bonus to the damagfe roll. Reaping strike's miss condition fails both of those parameters (it's not a hit and it's not a damage roll).