A diagonal of a polygon is an segment between two non-adjacent vertices of the polygon. How many diagonals does a regular 30-sided polygon have?  Choose the correct choice from the following choices
A) 875 B) 405 C) 1425 D) 2025 E) 2500
There's a direct formula for this.   Number of diagonals in a regular polygon = [n*(n-3)] / 2, n = number of sides of the regular polygon.   Here, n = 30.   Plugging it in, we get 405 diagonals!   Answer (405).
<result>B</result>
A diagonal of a polygon is an segment between two non-adjacent vertices of the polygon. How many diagonals does a regular 30-sided polygon have?