five
0.5*(402-120) = 740 diagonals
50*(50 - 3)/2 = 1175 diagonals.
The formula is: 0.5*(n2-3n) where n is the number of sides of the polygon. So: 0.5*(81-27) = 27 diagonals
It will have 7 sides
For an n-sided polygon, the number of diagonals is 1+2+3+....+(n-4)+2(n-3). For a nine-sided polygon, there are 1+2+3+4+5+2(6)=27 diagonals.
A pentagon has 5 diagonals.
There are five diagonals in a pentagon.
There are 5 diagonals in a pentagon
a pentagon has 5 diagonals i ur gud at maths...
A five sided pentagon has 5 diagonals
5 diagonals
A pentagon has 5 diagonals.
A pentagon has 5 diagonals
It has 5 diagonals
A pentagon has 5 diagonals.
A pentagon has 5 diagonals
there are 5, 6, or 7 diagonals in a pentagon