Question

Find the cube root of $2744$ by estimation method.

• A. $12$
• B. $14$
• C. $24$
• D. $16$

Answer 1

The correct option is B $14$

Step $I$: Form groups of $3$ starting from right most digit of $2744$, i.e. $\underset{–}{2}\underset{–}{744}$.
Then, the two groups are $744$ and $2.$

Here, $744$ has $3$ digit and $2$ has only $1$.

Step $II$: Take $744$.
Digit in unit place $=4$.
Therefore, we take one's place of required cube root as $4$ ....[Since, $4^3=64$].

Step $III$: Now, take the other group $2$.
We know, $1^3=1$ and $2^3=8$.
Here, the smallest number among $1$ and $2$ is $1$.
Therefore, we take $1$ as ten's place.
$\therefore \sqrt[3]{32744}=14$.

Hence, option $B$ is correct.