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  1. If the diameter of the cross-section of a wire is decreased by 5%,by what percentage should the length be increased so that the volume remains the same ?

  2. Surface areas of a sphere and cube are equal. Then find the ratioof their volumes.


Let us see some more examples.

Example-10.A solid toy is in the form of a right circular cylinder with hemispherical shape at one end and a cone at the other end. Their common diameter is 4.2 cm and the height of the cylindrical and conical portions are 12cm and 7cm respectively. Find the volume of the solid toy.

(use p = 22/7).

Solution : Let height of the conical portion h1 = 7cm
The height of cylindrical portion h2=12cm

Radius(r)=4.2/2=2.1=21/10cm

Volume of the solid toy

= Volume of the Cone + Volume of the Cylinder + Volume of the Hemisphere.



















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