If you mean the area of a regular octagon with 8 equal sides of 3 cm then by using trigonometry its area works out as 43.36 square cm rounded to two decimal places.
The area will depend on whether or not is it as regular octagon. there is nothing in the question to suggest that it is regular.
Geometric figures in a plane can be 3-sided (triangle), 4-sided (square, rectangle, or, in general, quadrilateral), 5-sided (pentagon), 6-sided (hexagon), 7-sided (heptagon or septagon), 8-sided (octagon) and on and on in the polygons.
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The flat shape (2-D) is an octagon. An eight-sided solid is an octahedron.
Formula for number of diagonals in an n-sided polygon is: number_of_diagonals = n x (n - 3) / 2 For an octagon, put n=8 in the above to get: number_of_diagonals_in_an_octagon = 8 x (8 - 3) / 2
There are 20 diagonals in an 8 sided octagon
In geometry a 29 sided shape is referred to as an icosikaidigon. The shape closely resembles an 3 dimensional octagon.
An octagon is an 8 sided 2 dimensional shape. A cylinder with the base of a hexagon (6 sided shape) would be an 8 sided 3 dimensional shape.
An octagon is an eight-sided figure. If a regular octagon has a perimeter of 24 inches, then each side will be 24 / 8 = 3 inches.
We have the triangle (3-sided), square (or quadrilateral, 4-sided), pentagon (5-sided), hexagon (6-sided), heptagon (or septagon, 7-sided), octagon (8-sided), nonagon (9-sided) and decagon (10-sided) to get you started.
The area of a 3 cm circle is: 7.069 square cm
Geometric figures in a plane can be 3-sided (triangle), 4-sided (square, rectangle, or, in general, quadrilateral), 5-sided (pentagon), 6-sided (hexagon), 7-sided (heptagon or septagon), 8-sided (octagon) and on and on in the polygons.
A circle with a radius of 3 cm has an area of 28.27 square cm.
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18 cm
The flat shape (2-D) is an octagon. An eight-sided solid is an octahedron.