[請加上繳交日期]F.2 MATH(急)

[size=3]1.In the figure,ABCD is a square with sides of 5 cm each,BD is an arc of a circle with the centre at A.
Find the area of the shaded region

2.A metal cube with sides of 10 cm each is melted and recast as 20 cylinders with the base radius of 1 cm.
Find the height of the cylinder.

3.There is some water inside a cylindrical container with the base radius of 6 cm.If a solid cylinder with the base radius of 2 cm is put into the container vertically to make water level rises,find the rise in the water level[/size]

[[i] 本帖最後由 cHoi_vy 於 2007-6-1 05:18 PM 編輯 [/i]]

2.(10x10x10)/20x1x2x3.14

1. 點解冇圖ge...................唔知道shaded area係咩wo = =

2.Let the height be h.
The volume of the metal cube = 10 x 10 x 10 = 1000cm3
The volume of one cylinder = (1^2) π h =  π h
The volume of 20 cylinder = 20πh

The volume of 20 cylinder = The volume of the metal cube
20πh = 1000
h = 50 / π = 15.9 (to 3 significant figure)

3. 唔識，因為唔知兩個cylinder的height
(可能計到ge，不過我笨，唔識= =)

第3條:
   條題目有問題,假如你放那個cylinder落去的時候is滿水
甘應該is  先求細cylinder個volume ,lethcm  be the height of the smaller cylinder
所以     π(2)^2.h=π(6)^2甘就求到升高個水的高度
希望幫到你