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 
Answer:8x10^-8
Step-by-step explanation:I am brainlyest
Answer:
The surface area of the prism is 108 square in.
Answer:
15 ways
Step-by-step explanation:

Answer:
4000 gallons.
Step-by-step explanation:
One day's discharge at the mouth of the river is 2 trillion gallons and it can supply all of country A's households for five months.
Now, if there are 100 million households in country A.
Then, the amount of water an average household uses each month will be given by
gallons. (Answer)