Question

A cuboidal metal of dimensions $44cm\times 30cm\times 15cm$ was melted and case into a cylinder of height $28cm$. Its radius is

• A. $20cm$
• B. $15cm$
• C. $10cm$
• D. None

Answer 1

Answer: (B)

$15cm$

Let radius of cylinder $=rcm$

Volume of cuboidal metal $=$ Volume of cylinder

$lbh=\pi r^{2}H$

$44\times 30\times 15=\frac{22}{7}\times r^2\times 28$

$r^2=\frac{44\times 30\times 15\times 7}{22\times 28}$

$r=\sqrt{15\times 15}=15cm$