Answer:
i. 9
ii. 14
iii. 405
iv. 
Step-by-step explanation:
The number of diagonals in a polygon of n sides can be determined by:

where n is the number of its sides.
i. For a hexagon which has 6 sides,
number of diagonals = 
= 
= 9
The number of diagonals in a hexagon is 9.
ii. For a heptagon which has 7 sides,
number of diagonals = 
= 
= 14
The number of diagonals in a heptagon is 14.
iii. For a 30-gon;
number of diagonals = 
= 
= 405
The number of diagonals in a 30-gon is 405.
iv. For a n-gon,
number of diagonals = 
The number of diagonals in a n-gon is 
6x-21>3
Add 21 to both sides
6x>24
Divide 6 on both sides
X>4
14x+11>-17
Subtract 11 from both sides
14x>-28
Divide 14 on both sides
X<-2
8(8x)
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Answer:
B. 22
Step-by-step explanation:
Quotient of 18 and 2 is 9, and just take the 9 out of the next series and you will be left with 22.