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Question
A solid cuboid of iron with dimensions 53 cm ⨯ 40 cm ⨯ 15 cm is melted and recast into a cylindrical pipe. The outer and inner diameters of pipe are 8 cm and 7 cm respectively. Find the length of pipe.
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Solution
Given,
The outer and inner diameters of pipe are 8 cm and 7 cm.
Dimensions of a solid cuboid of iron = 53 cm × 40 cm × 15 cm.
When a shape melted and recast into another shape volume will remain same.
Volume of cubical iron = volume of cylindrical pipe
length × breadth × height = π(R2 − r2)h
53 × 40 × 15 = `22/7 xx (4^2 - (7/2)^2)h`
53 × 40 × 15 = `22/7 xx 15/4 xx h`
h = `(53 xx 40 xx 15 xx 7 xx 4)/(22 xx 15)`
h = 2698.18 cm = 27 m [∵ 1 m = 100 cm]
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