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Question
A solid piece of iron of dimensions 49 × 33 × 24 cm is moulded into a sphere. The radius of the sphere is
Options
21 cm
28 cm
35 cm
none of these
Solution
The volume of iron piece = 49 × 33 × 24 cm3
Let, r is the radius sphere.
Clearly,
The volume of sphere = volume of iron piece
`4/3pir^3 = 49 xx 33 xx 24`
`4/3 xx 22 /7 xx r^3 = 49 xx 33 xx 24`
`r^3 = (49 xx 33 xx 24 xx 3 xx 7)/(4 xx 22)`
`r^3 = 49 xx 3xx 3 xx 3 xx 7`
`r = 7 xx 3`
`r = 21 cm`
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