By writing π/15 in terms of π/5 and π/3, show that it is possible to trisect π/5 and also possible to construct a regular 15-gon.
I'm not sure how breaking $\pi/15$ down like this would help me show that it's possible to trisect $\pi/5$... Any help would be great, thank you in advance!
(I'm starting to suspect that there is a typo -- missing a 1 in $\pi/5$ to make it 15 in the denominator)