Answer:
290 degrees
Explanation:
To find the length of the major arc subtracts 360-70.
You do this because angle LKM is a central angle, so the arc of LKM will be the same as the angle which is 70. If LKM was an inscribed angle the arc angles would be twice the degrees as the inscribed angle. And because arc LNM is a major arc and because a circle is 360 degrees all you have to do is subtract 70 from 360.
The image below shows an inscribed angle and a central angle.