An equiangular polygon is a polygon whose its vertex angles are equal.

All congruent polygon are _____.

If the measure of each exterior angle of a regular polygon is ${\left(51\frac{3}{7}\right)}^{\circ }$, then the ratio of the number of its diagonal to the number of its side is:

State whether the following polygon is regular or irregular and also write whether it is convex or concave.

In the figure,$ABCDEF$ is a regular hexagon. Prove that $△BDF,$ drawn by joining alternate vertices is equilateral.

In the figure, $ABCDEF$ is a regular hexagon. Prove that $ACDF$ is a rectangle.

Classify the given figure on the basis of the following: Simple curve / closed curve / polygon / convex polygon / concave polygon.