If we join the Center with different corners of the polygon,we find 10 Isoceles triangle with equal side=9.14cm, Making an angle of 36° between the equal sides.
Area of 1 triangle= a*b*sinC/2
= 9.14*9.14*Sin36°/2
= 9.14*9.14*0.587/2
=24.51 cm^2
Area of 10 triangle= 24.51*10
= 245.1cm^2
