Explanation:

Statement 1: Cos² α + cos² β = sin² γ

or cos² α + cos² β = 1- cos² γ

or cos² α+cos² β+cos² γ=1 which is true.

Statement 3: Using equation: cos² α + cos² β + cos² γ = 1

Or 1 - sin² α + 1 – sin² β + 1 – sin² γ = 1

Or sin² α + sin² β + sin² γ = 2

Therefore statement 3 is also correct and it implies that 2 is incorrect.