1) Bisect the 80 so you get 40 degree angle
2) Bisect the 40 so you get 20 degree angle
3) Get a 100 degree angle by extending one of the angle side
4) Bisect the 100 so you get 50 degree angle
5) Bisect the 50 so you get 25 degree angle
6) Bisect the 25 so you get 12.5 degree angle
7) Draw a new line
8) Copy the 20 degree angle and the 12.5 degree angle to together on the line to get a 32.5 degree angle