Question 261768
When Cammie finished making a friendship bracelet, it was 7.9 inches long. What was the diameter of the bracelet?
What formula would or should I use for this?
Do not understand.

Well if the bracelet approximates a circle then we can call the 7.9 inches the circumference.
The circumference of a circle is the length around the circle.
C circumference = 2 * pi * r = pi * d, where r is the radius (distance from center to edge of circle) and d is the diameter (width of the circle which is 2*r).

C = 7.9 = pi * d  (now solve for d and round to nearest tenth of an inch or hundredth of an inch)

7.9/pi = d
2.51 or 2.5 inches is approximately the diameter of the bracelet