Question

top surface of a raised platform is in the shape of a regular octagon as shown in figure find the area of octagon surface

Answer 1

Given: 

Sides of octagon= 5 m.

Construction:  We Divide the octagon in 3 figures, two are  trapeziums whose parallel and perpendicular

sides are 11 m and 5 m respectively and third figure in middle is rectangle

having length and breadth 11 m and 5 m.

Area of Trapezium

= (1/2) × (Sum of parallel sides) × Perpendicular distance

= (1/2) (11+5)4

= 16 x 2

= 32m²

Area of 2 trapeziums = 64 m²

Area of Rectangle = Length x Breadth

= 11 x 5 = 55

 Area of Rectangle = 55 m²

Total area of octagon = 64 + 55= 119

 

Total area of octagon = 119 m²

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Hope this will help you..

Answer 2

Step-by-step explanation:

Hence required area = 119 metre square