I'd like to use the Szemerédi-Trotter theorem (for all m, n $\leq$ 1, we have that the number of point-line incidences in a set of n points and m lines in $\mathbb{R}$$^2$ is at most O(m$^{2/3}$n$^{2/3}$ + m + n)) to prove that n points in the plane determine at most O(n$ ^{7/3}$) triangles that have a given fixed angle α.
Does anyone have a proof?