Volume (2)

2013-10-19 8:49 pm

1) The figure shows a prism consisting for identical cuboids, The base of each cuboid is a square of side x cm. The base area of the prism is 64cm².

http://i.imgur.com/p92xzHz.jpg

a) Find the value of x.
b) Find the total surface area of the prism.

2) In the figure, the sector COD is cut away from the sector AOB. The area of the shaded region ABCD is 6π cm². ∠AOB = 108°, OC = 4cm and BC = 2cm

http://i.imgur.com/v4WlcjG.jpg

Find the perimeter of the shaded region ABCD.
* The length of CD = 12π/5 cm and the length of AB = 18π/5 cm

3) In the figure, a semi-circular paper with centre O of radius 10cm is folded to form a right circular cone by joining OA and OB together.

Find the capacity of the cone.

* The base radius of the cone is 5cm

回答 (1)

用戶4366

2013-10-29 7:48 am

✔ 最佳答案

1. (10)(3x) = 64

(10)(x)(10) + (8)(x²)

2. = BC + CD + DA + AB

= 2 + 12π/5 + 2 + 18π/5

2013-10-19 14:14:56 補充：
3. Arc length of the semi-circular paper = (2πr/2) = πr = 10π

let radius of the cone be r₁
2πr₁ = 10π

let height of the cone be h
10² = (r₁)² + h²

體積 = (1/3)(底面積)(高)

2013-10-28 23:48:25 補充：

圖片參考：http://imgcld.yimg.com/8/n/HA00388954/o/20131028234521.jpg

如果圖太細，可以用滑鼠指住圖像，按右鍵，把圖存到電腦，再在電腦開啓，便可以看清楚了。

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