Area of a POLYGON
(1/2)*a*b*sin((2*pi)/*n).
here a=b=r;
so area of 1 triangle =
(1/2)*(r*r*sin((2*pi)/n))
so for the n triangles the total area is
area of polygon |
observe the figure more for detail
so now solve this problem
UVA 10432 (area of polygon)