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प्रश्न
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.
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उत्तर
Area of octagon = Area of (ABDC) + Area of (CDFE) + Area of (EFHG)
= `{1/2 [(5+11) xx 4] + (11 xx 5) + 1/2 [(5 + 11) xx 4]}m^2`
= `{1/2 (16 xx 4) + 55 + 1/2 (16 xx4)}m^2`
= `{1/2 xx 64 + 5 + 1/2 xx 64}m^2`
= {32 + 55 + 32}m2
= 119m2
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