李伯伯围了一个半圆形的菜地,它的面积是6.28㎡,现在李伯伯要在菜地周围围一圈
\u674e\u4f2f\u4f2f\u5728\u5c0f\u9662\u9760\u5899\u5904\u7528\u7bf1\u7b06\u56f4\u6210\u4e86\u4e00\u5757\u68af\u5f62\u83dc\u5730\u3002\u5df2\u77e5\u7bf1\u7b06\u957f40\u7c73,\u9ad8\u662f12\u7c73\uff0c\u8fd9\u5757\u83dc\u5730\u7684\u9762\u79ef\u662f\u591a\u5c11\u5e73\u65b9\u7c73\uff1f\u7bf1\u7b06\u4e0a\u5e95+\u4e0b\u5e95=40-12=28\u7c73
\u8fd9\u5757\u83dc\u5730\u7684\u9762\u79ef=1/2*28*12=168\u5e73\u65b9\u7c73
\u5468\u957f\u662f2\uff08\u957f\u52a0\u5bbd\uff09\u6240\u4ee5\u5148\u6c42\u957f\u52a0\u5bbd\u7684\u548c\uff1a
120\u00f72=60\uff08m\uff09
\u957f\u6709\u4e09\u4efd\uff0c\u5bbd\u6709\u4e24\u4efd\uff0c\u8981\u52a0\u8d77\u6765\u624d\u80fd\u8ba1\u7b97\uff1a
3+2=5\uff08m\uff09
\u957f\u6709\u5176\u4e2d\u4e09\u4efd\uff0c\u6240\u4ee5\uff1a60\u00f75\u00d73=36\uff08m\uff09
\u5bbd\u6709\u5176\u4e2d\u4e24\u4efd\uff0c\u6240\u4ee5\uff1a60\u00f75\u00d72=24\uff08m\uff09
\u5b83\u4eec\u9762\u79ef\u4e3a\uff1a36\u00d724=864
r=2
0.5×2×3.14×2=6.28m
绛旓細姹傞潰绉紵锛9.42梅3.14锛²脳3.14梅2=14.13骞虫柟绫
绛旓細杩欓亾棰樻病鏈夋彁鍑洪棶棰橈紝鏍规嵁棰樻剰鍙兘鏄兂鎻愬嚭杩欎釜鍗婂渾褰㈢绗嗙殑鍛ㄩ暱鍙婇潰绉槸澶氬皯锛熸垜浠互姝ゆ彁闂В棰樸傜敱浜庤繖涓鍗婂渾褰㈢殑绡辩瑔鐨勭洿寰勬槸6绫筹紝鑰屽渾鐨勫懆闀跨瓑浜2蟺?鍗婂緞锛屽渾鐨勯潰绉瓑浜幭?鍗婂緞鐨勫钩鏂广傛墍浠ヨ繖涓崐鍦嗙绗嗙殑鍛ㄩ暱绛変簬锛2?3.14?6/2锛/2=9.42绫筹紝杩欎釜鍗婂渾绡辩瑔鐨勯潰绉瓑浜庯紙3.14?6/2鐨勫钩鏂癸級/2=...
绛旓細鐩村緞涓24绫筹紝鍗婂緞r=12绫 鍒鍗婂渾褰鍛ㄩ暱涓合r=12蟺锛堢背锛
绛旓細鍗婂渾褰㈢殑楦¤垗绡辩瑔闀夸负9.42绫 鍗婂緞灏辨槸9.42梅3.14锛3绫 闈㈢Н灏辨槸3脳3脳3.14梅2
绛旓細鍗婂緞鏄9.42梅3.14=3 闈㈢Н锛3.14脳3脳3=28.26 涓嶈繃浣犵殑鍗曚綅濂藉儚涓嶅鍝
绛旓細鍗婂渾鐨鍛ㄩ暱涓28.26,鎵浠ュ崐寰勪负28.26/3.14=9绫筹紝鍒欓浮鑸嶉潰绉负3.14*9*9/2=127.17骞虫柟绫
绛旓細432
绛旓細灏辨槸鍗婁釜鍦嗗渾闀 3.14x4.5=14.13绫
绛旓細鍏绘畺鎴鏉庝集浼鐢ㄧ绗嗗缓閫涓涓崐鍦嗗舰鐨楦¤垗绡辩瑔闀25.7绫崇洿寰勬槸澶氬皯绫筹紵25.7梅锛3.14+2锛壝2 =25.7梅5.14脳2 =5脳2 =10绫
绛旓細鍗婂緞锛15.7梅3.14=5绫 闈㈢Н锛3.14脳5²梅2=39.25骞虫柟绫
