A square, a rhombus and a kite all have perpendicular diagonals that intersect at right angles
no
Regular polygons. A square and rectangle will have congruent (equal length) diagonals.
The principal diagonals of all regular polygons.
It is not possible to answer the question since there are no polygons "following".
square and rectangle
rectangle
All regular polygons.
It has 464 diagonals. I used n(n-3)/2. Works for all polygons.
Regular polygons with even sides if there are 6 or more of them; selected irregular polygons with seven or more odd numbers of sides.
squares,rectangles,regular pentagons
You cannot draw a diagonal from a vertex to itself. So that is 1. Also, the diagonals to the adjacent vertices on either side will actually be the sides of the polygon, not diagonals. Those are the other 2.
Any regular polygon. Lots of irregular polygons can also have congruent diagonals, for example a kite. The answer should not be "a square" because it is a rectangle - a special case but a rectangle nevertheless.