The crucial point is that, for a hexagon, the distance from any vertex to the center is the same as the length of each side. So, as the hint says, a hexagon can be divided into 6 equilaterial triangles. Do you know what "equilateral" triangles are? Do you know how to find the area of a triangle? Do you know how to find an altitude of an equilateral triangle? Do you see that each equilateral triangle can be divided into two right triangles? Do you know how to find the area of a right triangle?
