Using the notes' formula $k_a = \dfrac{c\alpha^2}{1-\alpha}$ with $c = 0.04$ and $\alpha = \dfrac{8}{17}$, what value is obtained for the dissociation constant?

Using the values from the notes: $k_a = \dfrac{0.04\times (8/17)^2}{1-8/17} = \dfrac{0.04\times 64/289}{9/17}$. The worked simplification in the notes gives $0.0167$.