<span>length of a diagonal of the square = </span>√(12^2 + 12^2)
= √(144 + 144)
= √288
= 16.97 cm
Answer:
or 4
Step-by-step explanation:

get rid of -2 by subtracting it from 21

Now you get your answer

Hope this helps! :)
The ar. of square =X^
=5.76
So,X=√5.76
=2.4
now, perimeter of square =4(X)
=4(2.4)
=9.6
So, the perimeter of the square is 9.6cm..
Thanks!
Hope it helps you..