For 1.
Solution,
Sides(l)= 3.5
Now,
Perimeter of square=4l
=4*3.5
=14
Then,
Area of square =l^2
=3.5*3.5
=12.25
For 2.
Solution,
Sides(l)=1
Now, perimeter of square =4l
=4*1
=4
Then,
Area of square =l^2
=1*1
=1
For 3.
Solution,
Sides(l)= 20
Now,
Perimeter of square=4l
=4*20
=80
Then,
Area of square =l^2
=20*20
=400