The approximate length is 21 cm.
EXPLANATION
Finding the length of the wire implies finding the perimeter of the semicircular pendant.
To find the perimeter of the pendant, we will use the formula below:
P = 2r + πr
Where P is the perimeter of the semicircle.
r is the radius of the semicircle.
π is a constant = 22/7
From the given question, r = 4.
Substitute the values into the formula and evaluate.
[tex]P=2(4)+\frac{22}{7}(4)[/tex][tex]=8+\frac{88}{7}[/tex][tex]=20.5714[/tex][tex]\approx21\text{ cm}[/tex]