Volume計cone既問題

2006-12-19 3:48 am
1.
The volume and height of a right circular cone are
108(pie)cm^3 and 9 cm respectively.Find its base
radius.

答案要(取至3位有效數字)

2.一個soild有兩個體,上邊個係cone,下邊個係圓柱體。
上邊個係cone slant height is 10cm.下邊個既圓柱體
既高度係10cm,個wide係12cm,要計個total surface
area of it(上邊個cone+埋下邊個圓柱體既total surface
area)答案係679cm^2(答案係取至三位有效數字)

plz help!

回答 (1)

2006-12-19 4:52 am
✔ 最佳答案
The volume and height of a right circular cone are
108(pie)cm^3 and 9 cm respectively.Find its base
radius.

(1/3)πr^2h=108 π
r^2h=324
9r^2=324
r=6 cm
2.一個soild有兩個體,上邊個係cone,下邊個係圓柱體。
上邊個係cone slant height is 10cm.下邊個既圓柱體
既高度係10cm,個wide係12cm,要計個total surface
area of it(上邊個cone+埋下邊個圓柱體既total surface
area)答案係679cm^2(答案係取至三位有效數字)
surface area of cone
= πrl
=π*6*10
=60π
surface area of 圓柱體
=2πrh+πr^2
=2π*6*10+36π
=156π
total surface area
=60π+156π
=216π
=679cm^2

2006-12-18 20:53:17 補充:
wide means diameter


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