Rosa is building a guitar. the second fret is 33.641\,\text{mm}33.641mm from the first fret. the third fret is 31.749\,\text{mm}31.749mm from the second fret. how far is the third fret from the first fret?

65.39 mm.

Step-by-step explanation:

We have been given that Rosa is building a guitar. The second fret is 33.641 mm from the first fret. The third fret is 31.749 mm from the second fret.

We can find the distance between third fret and first fret by adding the distances between first fret to second fret and second fret to third fret.

Therefore, 3rd fret is 65.39 mm away from 1st fret.