Explicație pas cu pas:
1. Hexagon (n-2)*180/n=(6-2)*180/6=720/6=120°
2. Octogon (n-2)*180/n=(8-2)*180/8=1080/8=135°
3. Heptagon (n-2)*180/n=(7-2)*180/7=900/7~128°35'
