What is the square number of 13 27 81 21 43 48 23 39 45

The given numbers are 13, 27, 81, 21,43, 48,23,39,45.

Square number is that number which is a perfect square means if you multiply a number by itself the number you obtained is a perfect square i.e it's square root is a natural number.

√13=not a natural number

√27=√3×√3×√3=3√3=irrational number

√81=√9×√9=9=a natural number

√21=not a natural number

√43=not a natural number

√48=4√3=not a natural number

√23=not a natural number

√39=not a natural number

√45=3√5=not a natural number

So, out of following numbers 13 27 81 21 43 48 23 39 45→81 is the only square number.

Option 3 - 81          

Step-by-step explanation:

Given : Numbers 13, 27, 81, 21, 43, 48, 23, 39, 45.

To find : What is the square number from given numbers ?

Solution :

Square number is defined as it is the product of some integer with itself.

To find the square number we have to take root of each number,

1)

Not a square number.

2)

Not a square number.

3)

It is a square number.

4)

Not a square number.

5)

Not a square number.

6)

Not a square number.

7)

Not a square number.

8)

Not a square number.

9)

Not a square number.

Therefore, Option 3 is a rational number.

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step-by-step explanation: