What do you need hepl on becasue i dont know
im pretty sure it's the first option.
Radius of curvature = 10'
Diameter of circle = 2 * 10' = 20'
height of segment = 2'
Let semi-chord be x.
Then by the intersecting chord property,
2*(20-2)=x^2
x^2=36
x=sqrt(36)=6
=>
chord=2x=2*6=12'
