更新1:
一枚十元硬幣環形部份的均勻闊度是0.4 cm ,如果該部份的面積是0.8兀 cm 2次方 ,求十元硬幣的半徑
F.2 扇形題
回答 (3)
2010-06-12 9:41 pm
✔ 最佳答案
(theta/360)x2(pi)(3)=4pitheta/60 =4
theta =240o
2010-06-12 14:02:02 補充：
(pi)r^2-pi(r-0.4)^2=0.8pi
r^2-(r^2-0.8r+0.16)=0.8
r^2-r^2+0.8r-0.16 =0.8
0.8r =0.96
r =1.2cm
2010-06-13 12:45 am
r/360*2pi*3=4pi
r=4*360/6=240(度)
r=4*360/6=240(度)
2010-06-12 9:10 pm
x/360 ‧2兀(3)=4兀
x=240
240度
x=240
240度
收錄日期: 2021-04-19 22:33:11
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20100612000051KK00677