Answer :

To determine the number of digits in a number whose square results in a 24-digit number, we can use properties of logarithms and exponents. Here is the step-by-step process:

1. Understand the Given Condition:
We are given that the square of a certain number results in a 24-digit number. Let this number be [tex]\( n \)[/tex].

2. Range of the 24-Digit Number:
A 24-digit number lies in the range:
[tex]\[ 10^{23} \leq n^2 < 10^{24} \][/tex]
This is because any number with 24 digits is at least [tex]\( 10^{23} \)[/tex] and less than [tex]\( 10^{24} \)[/tex].

3. Taking the Square Root:
To find the range for [tex]\( n \)[/tex], we take the square root of both sides of the inequality:
[tex]\[ \sqrt{10^{23}} \leq n < \sqrt{10^{24}} \][/tex]
Using the properties of exponents, the square roots can be simplified:
[tex]\[ 10^{11.5} \leq n < 10^{12} \][/tex]

4. Determine the Number of Digits:
We need to find the number of digits in [tex]\( n \)[/tex]. The number of digits in a number [tex]\( x \)[/tex] is given by [tex]\( \lfloor \log_{10}x \rfloor + 1 \)[/tex].

- For the lower bound [tex]\( 10^{11.5} \)[/tex]:
[tex]\[ \lfloor \log_{10}(10^{11.5}) \rfloor + 1 = \lfloor 11.5 \rfloor + 1 = 11 + 1 = 12 \][/tex]
- For the upper bound [tex]\( 10^{12} \)[/tex]:
[tex]\[ \lfloor \log_{10}(10^{12}) \rfloor + 1 = \lfloor 12 \rfloor + 1 = 12 + 1 = 13 \][/tex]

5. Conclusion:
Since [tex]\( n \)[/tex] lies between [tex]\( 10^{11.5} \)[/tex] and [tex]\( 10^{12} \)[/tex], the only digit count that fits within this range is 12.

Therefore, the number of digits in the certain number [tex]\( n \)[/tex] is 12.