Question

Find the tens digit of the cube root of each of the numbers. 

(i) 226981 

(ii) 13824 

(iii) 571787 

(iv) 175616

Answer 1

(i) 226981 

Let’s take number 226981. 

Unit digit = 1 

So unit digit in the cube root of 226981 = 1 

After striking out the units, tens and hundreds digits of 226981, 

Now we left with 226 only. 

As we know that 6 is the Largest number whose cube root is less than or equals to 

226(6³<226<7³). 

So, 

The tens digit of the cube root of 226981 is 6. 

(ii) 13824 

Let’s take number 13824. 

Unit digit = 4 

So unit digit in the cube root of 13824 = 4 

After striking out the units, tens and hundreds digits of 13824,

Now we left with 13 only. 

As we know that 2 is the Largest number whose cube root is less than or equals to 

13(2³<13<3³). 

So, 

The tens digit of the cube root of 13824 is 2. 

(iii) 571787 

Let’s take number 571787. 

Unit digit = 7 

So unit digit in the cube root of 571787 = 3 

After striking out the units, tens and hundreds digits of 571787, 

Now we left with 571 only. 

As we know that 8 is the Largest number whose cube root is less than or equals to 

571(8³<571<9³). 

So,

The tens digit of the cube root of 571787 is 8. 

(iv) 175616 

Let’s take number 175616. 

Unit digit = 6 

So unit digit in the cube root of 175616 = 6 

After striking out the units, tens and hundreds digits of 175616, 

Now we left with 175 only. 

As we know that 5 is the Largest number whose cube root is less than or equals to 

175(5³<175<6³). 

So, 

The tens digit of the cube root of 175616 is 5.