the diagram shows a sector of a circle of radius 8 units, formed from an angle of size 300 degrees. find the exact length of the arc.
So 300 / 360 = 5/6. The arc thus is 1/6 of the circumference.
The circumference is 8^2 π = 64π. 1/6 of that is 64π/6 = 32π/3.
If you don't understand anything feel free to ask!