Answer:
17
Step-by-step explanation:
The sum of all the angles of this polygon is
(n-2)180
Where m is the number of corners
(5-2)180
3*180
540
Hence
Sum of all angles=540
139+92+71+9x+5x=540
302+14x=540
14x=540-302
14x=238
Dividing both sides by 14
x=17
