Question:
Which of the following is a square of an even number?
(a) 144
(b) 169
(c) 441
(d) 625
Solution:
(a) Here, $144=(12)^{2}$
Similarly, $\quad 169=(13)^{2}$
$441=(21)^{2}$
$625=(25)^{2}$
Thus, 144 is a square of an even number.
Alternate Method
We know that, square of an even number is always an even number. Hence, 169, 441 and 625 are not even numbers. So, only 144 is an even
number, which is the square of 12.