Question

The figure below shows a large pencil. It consists of a cone, a cylinder and a hemisphere. Given that the base diameter is 14 cm and that the volume of the cone, the cylinder and the hemisphere are in the ratio 6 : 25 : 4, find the volume of the model
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Answer 1

Answer:

Given: Diameter of base of cylinder =14 cm.

∴ Radius (r)=

2

14

=7 cm.

and Height of cylinder is h=20 cm.

So, Surface area of cylinder =2πr(r+h)

=2×

7

22

×7(7+20)

=44×27

Surface area of cylinder =1188 sq.cm.

Volume of cylinder =πr

2

h

=

7

22

×7

2

×20

=22×7×20

Volume of cylinder=3080 cu.cm