Derive the area of a regular polygon??

Question

you know that the formular for the area of a regular polygon is:

Area=apothem(perimeter)

Why is that??

How did we reach that as the formula?

Answer 1

A regular polygon of n sides each of length a can be divided into n isosceles triangles. The apothem would be the altitude of each of these triangles. The area of each triangle would then be ½a(apothem). There are n triangles so the area of the polygon would be ½an(apothem). But an is the perimeter so the area would be ½ perimeter(apothem)

Note: the formula you have left out the ½

Answer 2

you have to be more specific than that.