9 Top surface of a raised platform is in the shape of a regular octagon as shown in the figure. Find the area of the octagonal surface.
Area of octagonal surface = Area of rectangular surface + 2(Area of trapezium surface)
Area of recatangular surface =
Area of trapezium surface =
So total area of octagonal surface = 55 + 2(32) = 55 + 64 = 119