# An iron pillar consists of a cylindrical portion 2.8 m high and 20 cm in diameter and a cone 42 cm high is surmounting it. Find the weight of the pillar, given that 1 cubic cm of iron weighs 7.5 gm. - Mathematics

An iron pillar consists of a cylindrical portion 2.8 m high and 20 cm in diameter and a cone 42 cm high is surmounting it. Find the weight of the pillar, given that 1 cubic cm of iron weighs 7.5 gm.

#### Solution

Volume of cylindrical portion

=pir^2h

= 22/7 xx (20/2)^2 xx 280

= 88000 cm^3

Volume of conical portion

=1/3pir^2h

 =1/3 xx 22/7 xx (10)^2 xx 42

=4400 cm^3

Total number

= 8800 + 4400

=92400

So total height

=92400 xx 7.5

= 693000 gm

= 693 kg

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#### APPEARS IN

RD Sharma Class 10 Maths
Chapter 14 Surface Areas and Volumes
Q 40 | Page 83