How many unique diagonals can be drawn in a five-sided convex polygon?

Guest Mar 22, 2015

2+0 Answers


Notice, that from each vertex, 2 diagonals can be drawn, giving us 10 diagonals. But the diagonal drawn from vertex A to vertex D would be the same diagonal drawn fro vertex D to vertex A.

So, we need to divide this by 2  = 5 diagonals.

Here's a pic to demonstrate this.....

pentstar.jpg (49409 bytes)


BTW....the number of diagonals that can be drawn in any regular polygon is given by....

[n*(n-3)] / 2     .... for n > 3



CPhill  Mar 22, 2015

6 Online Users

We use cookies to personalise content and ads, to provide social media features and to analyse our traffic. We also share information about your use of our site with our social media, advertising and analytics partners.  See details