Respuesta :
Answer:
nonagon/enneagon
Step-by-step explanation:
Let n be the number of length of the polygon
(n-2)x180 = 140n
180n - 360 = 140n
n = 9
The name of the polygon is call nonagon/enneagon
- 140= (n-2)×180/n
- 140n=180n-360
- 180n-140n=360
- 40n=360
- n=360/40
- n=9