PRINT INPUT PROMPT "正○角形? ":n INPUT PROMPT "外接円の半径は? ":r PRINT LET a=SQR(2)*r*SQR(1-COS(2*PI/n)) ! 二等辺三角形の余弦定理より LET b=SQR(r^2-(a/2)^2) PRINT "1辺の長さ:";a PRINT "内接円の半径:";b PRINT END