圆面积=4,2x4,2x3,1416=55,417824
长方形长=55,417824/4,2=13,1947
阴影部分的周长=(13,1947+4,2)x2-4,2x2+4,2x3,1416/2
=34,7894-8,4+6,59736
=32,98676
≈33 cm
圆面积=4,2x4,2x3,1416=55,417824
长方形长=55,417824/4,2=13,1947
阴影部分的周长=(13,1947+4,2)x2-4,2x2+4,2x3,1416/2
=34,7894-8,4+6,59736
=32,98676
≈33 cm