How to Calculate lengths of diagonals for an irregular polygon?

[TammyTam]

Does any one know if there is a tool that will allow calculations of lengths of dianganals for irregular polygons?

Tammy

[TammyTam]

Hi There,

I have polygons of estuaries and would like to find the distance from the mouth of the river to the other side of the polygon.  Basically a straight line distance.  However, the shape of the estuary can differ. Any suggestions?

Thank you so much for your help.