Recall that to compute the arc length with a central angle given in degrees, we can use the following formula:

where r is the radius of the circle, and θ is the central angle.
Substituting θ = 70°, and r = 4 yd in the above formula, we get:

Simplifying the above result, we get:

Now, to determine the arclength of LNM, first, we determine the perimeter of the circle:

Now we subtract the arclength of LKM and get:

Answer:
