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.

Explanation

Area of octagon ABCDEFGH =area of trapezium ABCH + area of rectangular HCDG +
area of trapezium EFGD

Side of the regular octagon = 5cm

Area of trapezium ABCH = Area of trapezium EFGD

Area of trapezium `ABCH=1/2xx(AB+CH)xxAI`

`=1/2xx(5m+11m)xx4m`

`=1/2xx16mxx4m`

`=32m^2`
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