Q4 of 6 Page 116

Find the cube root of 91125 using estimation.

Given Number is 91125


Step 1: Form groups of three starting from the rightmost digit of 91125


91 125


In this case, one group, i.e., 125 has three digits whereas 91 has only one digit.


Step 2: Take 125. The digit 5 is at its one’s place. We take the one’s place of the required cube root as 5.


Step 3: Take the other group, i.e., 91. Cube of 4 is 64, and cube of 5 is 125. 91 lies between 64 and 125. The smaller number among 4 and 5 is 4. The one’s place of 4 is 4 itself. Take 4 as ten’s place of the cube root of 91125


i.e.


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