document.write( "Question 554031: how do you to find the length of a side of a octagon with only the measurement of the total area(35cm^2) \n" ); document.write( "
Algebra.Com's Answer #361174 by Alan3354(69443)\"\" \"About 
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how do you to find the length of a side of a octagon with only the measurement of the total area(35cm^2)
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\n" ); document.write( "If it's a regular octagon, it's comprised of 8 isoceles triangles having vertex angles of 45 degs, each with an area of 35/8 sq cm.
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\n" ); document.write( "b = length of sides
\n" ); document.write( "h = height of triangle (the apothem of the octagon)
\n" ); document.write( "(b/2)/h = tan(22.5)
\n" ); document.write( "b = 2h*tan(22.5)
\n" ); document.write( "h = (b/2)*cot(22.5)
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\n" ); document.write( "b*h/2 = 35/8 (Area of 1 triangle)
\n" ); document.write( "\"%28b%5E2%2F2%29%2Acot%2822.5%29+=+35%2F8\"
\n" ); document.write( "\"b+=+sqrt%2835%2Atan%2822.5%29%2F4%29\"
\n" ); document.write( "b =~ 1.904 cm
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\n" ); document.write( "You can use the formula for area of a polygon with n sides of length s:
\n" ); document.write( "\"Area+=+ns%5E2%2Acot%28180%2Fn%29%2F4\"
\n" ); document.write( "Applies to all regular polygons
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