Question

Find the cube root of $238328$ by estimation method.

• A. $52$
• B. $62$
• C. $72$
• D. $182$

Answer 1

Answer: (B)

$62$

Step $I$: Form groups of $3$ starting from right most digit of $238328$, i.e. $\overline{238}\overline{328}$.

Then, the two groups are $238$ and $328.$

Here, $238$ has $3$ digit and $328$ has $3$ digit.

Step $II$: Take $328$.

Digit in unit place $=8$.

Therefore, we take one's place of required cube root as $2$ ....[Since, $2^3=8$].

Step $III$: Now, take the other group $238$.

We know, $6^3=216$ and $7^3=343$.

Here, the smallest number among $6$ and $7$ is $6$.

Therefore, we take $6$ as ten's place.

$\therefore \sqrt[3]{3238328}=62$.

Hence, option $B$ is correct.