求圓周:(兀=3.14)
1)正方形咭紙邊長1.2m,現要剪出一個最大的圓形,圓周是多少?
2)大圓直徑20cm,小圓半徑5cm,大、小圓的圓周差多少?
3)長方形長2m ,闊0.8m,現要剪出兩個最大的圓形,每個圓周是多少?
4)大圓半徑12cm,小圓直徑12cm,大、小兩圓的圓周差多少?
5)圓形的直徑是8cm,如果把直徑增加2cm,圓周增加了多少?
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T&F
1)12×2×3.14=75.36
2)6.5×2×3.14=40.82
3)18×3.14=56.52
4)0.7×3.14=2.198
5)0.6×3.14×500=942
☆★☆★圓周☆★☆★
2008-05-21 6:15 am
回答 (3)
2008-05-21 6:43 pm
✔ 最佳答案
答案如下:1. 可剪出直徑最長為1.2m的圓形:
圓周 = 1.2 × 3.14 = 3.768m
2. 大、小圓的圓周相差
= 20 × 3.14 - 5 × 2 × 3.14
= (20 - 10) × 3.14
= 10 × 3.14
= 31.4cm
3. 可剪出直徑最長為0.8m的圓形:
每個圓周 = 0.8 × 3.14 = 2.512m
4. 大、小圓的圓周相差
= 12 × 2 × 3.14 - 12 × 3.14
= (24 -12) × 3.14
= 12 × 3.14
= 37.68cm
5. 圓周增加了
= (8 + 2) × 3.14 - 8 × 3.14
= (10 - 8) × 3.14
= 2 × 3.14
= 6.28cm
2008-05-27 5:57 am
1)1.2X3.14=3.768
2)20X3.14-5X2X3.14=31.4
3)0.8X3.14
4)12X2X3.14-12X3.14=37.68
5)(8+2)X3.14-8X3.14=6.28
2008-05-26 21:58:00 補充：
3)0.8X3.14=2.512
2)20X3.14-5X2X3.14=31.4
3)0.8X3.14
4)12X2X3.14-12X3.14=37.68
5)(8+2)X3.14-8X3.14=6.28
2008-05-26 21:58:00 補充：
3)0.8X3.14=2.512
2008-05-22 12:34 am
1. The circumference=(1.2x3.14)cm
=3.768cm
2.The diffrence=(3.14x(20-5x2))cm
=(3.14x10)cm
=31.4cm
3.the circumference=(0.8x3.14)m
=2.512m
4. the diffrence=(3.14x12)cm
=37.68cm
5.the increase=(3.14x2)cm
=6.28cm
=3.768cm
2.The diffrence=(3.14x(20-5x2))cm
=(3.14x10)cm
=31.4cm
3.the circumference=(0.8x3.14)m
=2.512m
4. the diffrence=(3.14x12)cm
=37.68cm
5.the increase=(3.14x2)cm
=6.28cm
參考: me
收錄日期: 2021-05-03 02:17:45
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20080520000051KK03046