某仿古钱币直径为4厘米，钱币内孔

某仿古钱币直径为4厘米，钱币内孔边缘恰好是圆心在钱币外缘均匀分布的等弧（如图）．求钱币在桌面上能覆盖的面积为9\7c(B6K:t,b6f0o6h平方厘米。2n:A-~8C

                                                                                                                                       2n:A-~8C