How many diagonals does a polygon with 13 sides have, if one of its vertices does not connect to any diagonal? Choose one.
A) 65
B) 62
C) 58
D) 54
E) 60
If I calculate it using the formulae, #diagonals = n (n-3)/2Each vertex sends of n-3 diagonals   n= 13-1 then 12*(12-3)/2= 
<gadget id="calculator">12*(12-3)/2</gadget>
<output>54</output>
54   Correct Option:54
<result>D</result>
How many diagonals does a polygon with 13 sides have, if one of its vertices does not connect to any diagonal?