一个环形铁片,外圆半径是4cm内圆半径是3cm,它的面积多少

2025-04-02 17:31:15
推荐回答(1个)
回答1:

4²×π-3²-π

=16×3.14-9×3.14
=50.24-28.26
=21.98(cm²)