Uh oh! Wolfram|Alpha doesn't run without JavaScript.
Please enable JavaScript. If you don't know how, you can find instructions
here
.
Once you've done that, refresh this page to start using Wolfram|Alpha.
(1-cos(12*pi/n))/(1-cos(2*pi/n))=26.74554032
(1-cos(12*pi/n))/(1-cos(2*pi/n))=26.74554032
Natural Language
Math Input
Extended Keyboard