Hello,
We know that the wire is 18.84 cm long, so the Circumference of the circle will be 18.84 cm.
Here is the formula:
C=πd where d represent diameter
Apply the information that we had into this formula
18.84=πd
Divided π from both side
18.84/π=πd
d≈6 cm. As a result, the diameter of the bracelet is 6 cm. Hope it help!