How do I find the angle of a sector with only the radii 5 and the arc length 4.4?Please write method

The circumference or periphery of a circle equals an arc length of a sector with an angle of 360°. Which happens to add up to 2pi*r. Given a radius r=5 we get:
2pi*5 = 10pi ~= (more or less) 31.42

So, we know the arc length of 4.4 and now we do a bit rule of three:

(360° / 31.42) = ( x° / 4.4) where x° is the angle you are looking for)
rearranging leads to:
x° = 4.4 * (360° / 31.42) = 50.4°
More or less as already mentioned above ;-)