1) 有個直立圓錐體沿其底平行的平面切成A,,B,,C三個部份,搵B同C ge曲面面積之比??
a. 1:3.6
b. 4:9
c. 8:25
d. 9:36
(A在頂,B在中,C在底;A高1 CM,B高2 CM,C高 3CM)
2)球形肥皂泡GE表面面積増加了96%,搵該肥皂泡GE百分増加?
錐體同球體ge問題???
2008-03-03 5:45 am
回答 (2)
2008-03-03 7:20 am
✔ 最佳答案
1.surface area of A : 1^2 = 1
surface area of B : (1 + 2)^2 - 1 = 8
surface area of C : (1 + 2 + 3)^2 - (1 + 2)^2 = 25
so ratio = 8 : 25
Ans : C
2.
I think you want the vloume decreased
let the origin sphere surafce area be x^2.
New = 1.96x^2
then radius decreased : 1.4x
then volume decreased :
= [(1.4x)^3 - x^3]/x^3 * 100%
= 177.4%
2008-03-03 7:09 pm
我來潑冷水...
surface area of C : (1 + 2 + 3)^2 - (1 + 2)^2 = 27(not25)
而且你的答案似乎有問題
睇下D 9:36(點解唔寫1:4)
2.答案:177.4%(上面答左)
surface area of C : (1 + 2 + 3)^2 - (1 + 2)^2 = 27(not25)
而且你的答案似乎有問題
睇下D 9:36(點解唔寫1:4)
2.答案:177.4%(上面答左)
收錄日期: 2021-04-21 13:20:40
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