<Table> <Tr> <Td> <Dl> <Dd> Downsize the angle AMC (also 60 °) with four angle bisectors and make a thirds of circular arc MON with an approximate solution between angle bisectors w and w . </Dd> <Dd> Straight auxiliary line g aims over the point O to the point N (virtually a ruler at the points O and N applied), between O and N, therefore no auxiliary line . </Dd> <Dd> Thus, the circular arc MON is freely accessible for the later intersection point R . <Dl> <Dd> ∠ (\ displaystyle \ scriptstyle \ angle ()) AMR = 19.999999994755615...° </Dd> <Dd> 360 ° ÷ 18 = 20 ° </Dd> <Dd> ∠ (\ displaystyle \ scriptstyle \ angle ()) AMR - 20 ° = - 5.244...E-9 ° </Dd> </Dl> </Dd> <Dd> Example to illustrate the error: </Dd> <Dd> At a circumscribed circle radius r = 100,000 km, the absolute error of the 1st side would be approximately - 9 mm . </Dd> <Dd> See also the calculation nanogan (Berechnung, German) </Dd> <Dd> 6.0 ∠ (\ displaystyle \ scriptstyle \ angle ()) JMR equivalent ∠ (\ displaystyle \ scriptstyle \ angle ()) AMR . </Dd> </Dl> </Td> </Tr> </Table> <Tr> <Td> <Dl> <Dd> Downsize the angle AMC (also 60 °) with four angle bisectors and make a thirds of circular arc MON with an approximate solution between angle bisectors w and w . </Dd> <Dd> Straight auxiliary line g aims over the point O to the point N (virtually a ruler at the points O and N applied), between O and N, therefore no auxiliary line . </Dd> <Dd> Thus, the circular arc MON is freely accessible for the later intersection point R . <Dl> <Dd> ∠ (\ displaystyle \ scriptstyle \ angle ()) AMR = 19.999999994755615...° </Dd> <Dd> 360 ° ÷ 18 = 20 ° </Dd> <Dd> ∠ (\ displaystyle \ scriptstyle \ angle ()) AMR - 20 ° = - 5.244...E-9 ° </Dd> </Dl> </Dd> <Dd> Example to illustrate the error: </Dd> <Dd> At a circumscribed circle radius r = 100,000 km, the absolute error of the 1st side would be approximately - 9 mm . </Dd> <Dd> See also the calculation nanogan (Berechnung, German) </Dd> <Dd> 6.0 ∠ (\ displaystyle \ scriptstyle \ angle ()) JMR equivalent ∠ (\ displaystyle \ scriptstyle \ angle ()) AMR . </Dd> </Dl> </Td> </Tr> <Dl> <Dd> Downsize the angle AMC (also 60 °) with four angle bisectors and make a thirds of circular arc MON with an approximate solution between angle bisectors w and w . </Dd> <Dd> Straight auxiliary line g aims over the point O to the point N (virtually a ruler at the points O and N applied), between O and N, therefore no auxiliary line . </Dd> <Dd> Thus, the circular arc MON is freely accessible for the later intersection point R . <Dl> <Dd> ∠ (\ displaystyle \ scriptstyle \ angle ()) AMR = 19.999999994755615...° </Dd> <Dd> 360 ° ÷ 18 = 20 ° </Dd> <Dd> ∠ (\ displaystyle \ scriptstyle \ angle ()) AMR - 20 ° = - 5.244...E-9 ° </Dd> </Dl> </Dd> <Dd> Example to illustrate the error: </Dd> <Dd> At a circumscribed circle radius r = 100,000 km, the absolute error of the 1st side would be approximately - 9 mm . </Dd> <Dd> See also the calculation nanogan (Berechnung, German) </Dd> <Dd> 6.0 ∠ (\ displaystyle \ scriptstyle \ angle ()) JMR equivalent ∠ (\ displaystyle \ scriptstyle \ angle ()) AMR . </Dd> </Dl> <Dd> Downsize the angle AMC (also 60 °) with four angle bisectors and make a thirds of circular arc MON with an approximate solution between angle bisectors w and w . </Dd>

How many lines of symmetry does a 18 sided polygon have