Show that the total energy eigenfunctions 210 (r, , ) and 211 (r, , )

Show that the total energy eigenfunctions ψ₂₁₀ (r, θ, ∅) and ψ₂₁₁ (r, θ, ∅) are orthogonal. Do you have to integrate over all three variables to show that the functions are orthogonal?