A)
A polygon is a closed shape so there must be at least three sides. Therefore, the least value that n can be would be three.
b)
n value
3 0
n(n-3)/2
3(3-3)/3
3(0)/3
0/3
0
4 2
n(n-3)/2
4(4-3)/2
4(1)/2
4/2
2
5 5
n(n-3)/2
5(5-3)/2
5(2)/2
10/2
5
3.174 is closer to 3.2 because, when rounding, 0.07 rounds up to 0.2.