The correct option is
C 3 cmWe know that,
square has all sides of equal length.
Now, let's consider length of side of square be
l cm.
Perimeter of square = length of side AB + length of side BC + length of side CD+ length of side DA
=
l+l+l+l
=
4l
Now, as given, perimeter of square is 12 cm.
∴ 4l =
12 cm
Using
trial and error method,
Putting
l =
1 cm in the LHS of the generated equation,
we get
4×1 cm =
4 cm.
Hence, LHS is not equal to RHS.
Putting
l =
2 cm in the LHS of the generated equation,
we get
4×2 cm =
8 cm.
Hence, LHS is not equal to RHS.
Putting
l =
3 cm in the LHS of the generated equation,
we get
4×3 cm =
12 cm
Hence, LHS = RHS.
∴ Length of each side of square is
3 cm.