Question

A cuboidal metal of dimensions $44cm\times 30cm\times 15cm$ was melted and cast into a cylinder of height $28cm$. Find its radius.

• A. $20cm$
• B. $15cm$
• C. $10cm$
• D. $30cm$

Answer 1

Answer: (B)

$15cm$

Given: Cuboidal metal was melted and cast into the cylinder of height $h$.

Therefore, Volume of cuboidal metal $=$ Volume of cylinder

$\Rightarrow l\times b\times h=\pi r^{2}h$

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

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

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