Question

Find the cube root of 238328 by estimation method.
a. 52
b. 62
c. 72
d. 182

Answer 1

Hint: In cube root generally, we use prime factorization method for small numbers but here digit is large so we will use estimation method for the find cube of the last digit.

Complete step-by-step answer:
238328 is an even number so its cube root has to be an even number.

Make 2 groups 238 328

First Group- 328-unit digit is 8 so unit digit of cube will be 2.

Second Group- 238 it lies between 6cube \[=216\] and 7 cubes \[=343\]

So take the smaller number 6 as tens place

Therefore, cube root of \[=238328=62\]
The correct option is B.

Note: For small numbers we can find the cube root by the Prime Factorization method but for large numbers it is not possible to do the Prime Factorization method. So for large numbers we should use estimation methods. By this we can get accurate answers in a very short time.