Octagon Calculator

Calculating a regular octagon (a polygon with eight vertices). This form is well known to us, as it is used on some road signs.

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Octagon calculator, enter one known value

Side length (a)
Smaller diagonal (d1)
The middle diagonal (e)
Large diagonal (d3)
Perimeter (p)
Square (S)
The radius of the circumscribed circle (R)
Radius of the inscribed circle (r)

Formulas:

d = a * √4 + 2 * √2
e = a * ( 1 + √2 )
f = a * √2 + √2
Height = e = 2 * r
Р = 8 * а
S = 2 * a2 * ( 1 + √2 )
R = a / 2 * √4 + 2 * √2
r = a / 2 * ( 1 + √2 )
Angle: 135°, 20 diagonals.