Each side of Pentagon is forming a triangle with third vertices being center of pentagon .
this way we get 5 triangles .
The line drawn from center to the mid point of side of pentagon is perpendicular line , that is height of triangle
ARea of such one triangle =
( 1/2)( side of pentagon )* height of the triangle )
(1/2)( 11.8 )( 8.1) = 47.79 square inch
Area of the pentagon = 5 times area of one such triangle =
5* 47.79 = 238.95
Answer : 238 .95 square inch