已知：一个圆锥形帐幕高8m，用帆布188m2．取π=．求这帐幕所覆盖的地面的面积（精确到1m2）．
直接写出得数﹣=﹣=﹣=+=+=﹣=+=﹣=
直接写出得数．+=﹣=+=﹣= 10﹣﹣=====．
直接写得数===== 1﹣= 1﹣==
直接写出得数.+= 1﹣=﹣= 2.5×3.8×4=+= 10﹣9.12=+0.25= 0.65×9+0.65=
计算下面各题，能简算的要简算． ．
m2．取π=
．求这帐幕所覆盖的地面的面积（精确到1m2）．
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= 2.5×3.8×4=
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= 10﹣9.12=
+0.25= 0.65×9+0.65=
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