Question

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

Answer 1

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.

Answer 2

Answer:

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) $\sqrt{13}=3.60$

Not a square number.

2) $\sqrt{27}=5.19$

Not a square number.

3) $\sqrt{81}=9$

It is a square number.

4) $\sqrt{21}=4.58$

Not a square number.

5) $\sqrt{43}=6.55$

Not a square number.

6) $\sqrt{48}=6.92$

Not a square number.

7) $\sqrt{23}=4.79$

Not a square number.

8) $\sqrt{39}=6.24$

Not a square number.

9) $\sqrt{45}=6.70$

Not a square number.

Therefore, Option 3 is a rational number.