One part of an iron - pillar is cylindrical and the rest part is conical . The radii of the cylindrical and conical part 8 cm and their heights are 240 cm and 36 cm respectively , If the weight of 1 cc iron be 7.8 gm , what will be the total weight of the pillar ?

Explanation

The radius of the cylindrical part = 8 cm and its height = 240 cm
` :.` the volume of the cylindrical part ` = 22/7 xx 8^(2) xx 240 ` cubic cm
` = 22/ 7 xx 64 xx 240 ` cc
Again , the radius of the conical part = 8 cm and its height = 36 cm
` :. ` the volume of the conical part ` = 1/3 xx 22/7 x 8^(2) xx 36 ` cc
` = 22/7 xx 64 xx 2 ` cc
So, the total volume of the pillar ` = ( 22/7 xx 64 xx 240 + 22/7 xx 64 xx 12) ` cc
` = 22/7 xx 64 xx( 240 + 12 )` cc
Now, the weight of 1 cc pillar is 7.8 gm
` :.` the weight of 1 cc pillar is 7.8 gm
` :. ` the weight of 1 cc pillar is 7.8 gm
` :.` the weight of 1 cc pillar is 7.8 gm
` :. ` the weight of ` 22/7 xx 64 xx 252 ` cc is `7.8 xx 22/7 xx 64 xx 252 ` gm
= 395366.4 gm
= 395 . 3664 kg
Hence the weight of the total pillar = 395.37 kg (approx )