求陰影部份的面積。
http://img185.imageshack.us/img185/9543/1234xx1.png
f.2數...急!!(扇形面積)
2006-12-14 4:20 am
回答 (6)
2006-12-14 4:26 am
✔ 最佳答案
π(10+15)^2 X 150/300 - π(10)^2 X150/300=312.5π-50π
=824.67
2006-12-14 4:33 am
π(10+15)²x150/360-π(10)²x150/360
=150/360(625π-100π)
=5/12(525π)
=218.75π
=687.22cm²
=150/360(625π-100π)
=5/12(525π)
=218.75π
=687.22cm²
2006-12-14 4:30 am
應該係咁....
扇形面積係 π r^2 x 扇形角度/360度
(10+15)^2 x 3.14 x 150/360 - 10^2 x 3.14 x 150/360
= (25^2 - 10^2 ) x 150/360 x 3.14
= 525 x 150/360 x 3.14
= 686.875 cm^2
^2 即係2次方咁解...
扇形面積係 π r^2 x 扇形角度/360度
(10+15)^2 x 3.14 x 150/360 - 10^2 x 3.14 x 150/360
= (25^2 - 10^2 ) x 150/360 x 3.14
= 525 x 150/360 x 3.14
= 686.875 cm^2
^2 即係2次方咁解...
參考: me
2006-12-14 4:29 am
面積
OCD-OAB=ABCD
(3.14)*(10+15)^2(150/360)-(3.14)*(10)^2(150/360)
ABCD=687cm^2
=(875)(Pi)/4
ps.扇形面積=Pi*半徑*半徑*(扇形角度/整個圓的角度)
OCD-OAB=ABCD
(3.14)*(10+15)^2(150/360)-(3.14)*(10)^2(150/360)
ABCD=687cm^2
=(875)(Pi)/4
ps.扇形面積=Pi*半徑*半徑*(扇形角度/整個圓的角度)
2006-12-14 4:29 am
25 x 25 x 3.14 x 150/360 - 10 x 10 x 3.14 x 150/360
2006-12-14 4:25 am
25*3.14/3= A
10*3.14/3 = B
A-B = c
10*3.14/3 = B
A-B = c
收錄日期: 2021-04-12 23:52:26
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20061213000051KK03977