Question

Regular polygon is not only equilateral but also.

Answer 1

Regular polygon are those which have all the sides equal and also all the interior angles equal to each other.
for example-
In regular hexagon, all of its six sides are equal to each other and all of its six angles are also equal to each other.

In the above hexagon, sides $AB=BC=CD=DE=EF=FA$
and angles $\angle A=\angle B=\angle C=\angle D=\angle E=\angle F$.
So, Hexagon $ABCDEF$ is REGULAR hexagon.

Hence, all the regular polygons are not only equilateral(having all sides equal) but also equiangular(having all angles equal).