Answer: 38.31 inches
Explanation:
We can think on the round lamp as a circle, then the inches of beads that she will need to go around the lamp is equal to the perimeter of the lamp.
The perimeter of a circle of diameter D, is:
Perimeter = pi*D
where pi = 3.14
In this case, we know that the diameter is 12.2 inches.
Replacing that in the above equation we get that the diameter of the lamp is:
Perimeter = 3.14*12.2 in = 38.31 in
Then Michelle needs 38.31 inches of the beads to go around the lamp.