Question

Can a 10 sided polygon have exactly 21 diagonals? Use the formula n(n-
3)/2 *

Answer 1

Answer:

No

Step-by-step explanation:

for a n-agon the formula is

$\frac{n(n-3)}{2}$

so in our case n=10

$\frac{(10)(10-3)}{2} \\\\=\frac{10*7}{2} \\\\=5*7\\\\=35$

so no, a 10 side polygon has exactly 35 diagonals