6. 正多边形的计算

正多边形的计算见表1-35。表1-35正多边形的计算　边数α(°)ar面积S34567891012162024324860901081201351401441501621651.732r1.414r1.176r1.000r0.868r0.765r0.684r0.618r0.518r0.390r0.313r0.261r0.196r0.131r0.577a0.707a0.851a1.000a1.152a1.307a1.462a1.618a1.932a2.563a3.196a3.831a5.101a7.64 ......（本文共 631 字 ）     [阅读本文] >>