document.write( "Question 970158: A regular octagon with sides of length 8 cm is inscribed in a circle. Find the radius of the circle to the nearest centimeter. I don't even know where to start and I don't have an answer provided. Thank for your help! \n" ); document.write( "

Algebra.Com's Answer #592826 by AnlytcPhil(1806) $\"\"$ $\"About$

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A regular octagon with sides of length 8 cm is inscribed in a circle.
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document.write( "The octagon is made up of 8 congruent isosceles triangles\r\n" );
document.write( "whose legs are radii of the circle.\r\n" );
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document.write( "We know that each of those congruent isosceles triangles \r\n" );
document.write( "has a 45°-vertex angle because 360° divided by 8 is 45°.\r\n" );
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document.write( "Because the triangles are isosceles, the base angles\r\n" );
document.write( "are congruent (equal in measure).  So the sum is found by\r\n" );
document.write( "subtracting 180°-45° =  135°, and each base angle is half\r\n" );
document.write( "of that or 67.5°.\r\n" );
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document.write( "Have you studied the law of sines?  There's another way to\r\n" );
document.write( "get the solution without using the law of sines, but if \r\n" );
document.write( "you've studied the law of sines, that's the easiest way:\r\n" );
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document.write( "Or R = 10 cm. to the nearest centimeter.\r\n" );
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document.write( "Edwin

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