暇つぶし2chat MATH - 暇つぶし2ch740:692 24/04/30 14:06:32.35 ElCKljKY.net 正7角形の辺長が1のとき R = 1/{2sin(π/7)} = 1.15238243548 (辺長) = 2y = 1.309071871314 R = 1.508551431285 >>694 では AB 1.50855153 BC 1.50855124 CD 1.50855116 DA 1.50855141 AC/√2 1.50855112 BD/√2 1.50855155