Step-by-step explanation:
It appears that given geometrical shape is a HEXA-DECAGON or a 16 sided polygon.
Measure of one interior angle of hexa-decagon can be given as:

No they're not proportionate because 9 divided by 4 = 2.25 and 11 divided by 6 is 1.83 so they're not the same in value
Answer:
use the distributive property to distribute the 8
-16+16n+3n=40+5n
-16+19n=40+5n
-16=40+5n-19n
-16=40-14n
-14n+40= -16
-14n= -16-40
-14n= -56
n= -56/-14
n= 4