A solid is formed by a right circular cone and a hemisphere with the same base. The radius of the sector that makes up the cone is 10cm and its angle at the centre is 216degree. Let the base radius of the hemisphere is r cm,
1) find the base radius of the hemisphere.
2) Which part of the solid, the right circular cone or the hemisphere, has a large surface area? How much larger? (Express your answer in terms of π.)
About areas and volumes
2009-03-15 8:58 pm
回答 (1)
2009-03-16 4:37 am
✔ 最佳答案
1)2π(10)(216/360) = 2πr
r=6
2) surface area of circular cone
= π(10)2(216/360)
=60π
surface area of hemisphere
=2π(6)2
=72π
so, the hemisphere has a larger surface area than the right circular cone by 12π.
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