Answer:
4.19 inches
Step-by-step explanation:
Your goal is to find the circumference of the donut and then divide that by 3 to get 1/3 of the outer edge of the donut.
Circumference is 2r
The diameter (double the radius) is 4, so radius (r) is 2
2 * pi * 2 = 4 pi = 12.57 (round to hundredth)
12.57/3 = 4.19
keep in mind that dividing by 3 is the same as multiplying by 1/3