If a curve is designated as a 3° curve on a 40 m arc length, what is the radius of the curve?

A surveyor is conducting a compass survey between two stations, A and B. The observed fore bearing (FB) of line AB is 124°30'. Determine the back bearing (BB) of line BA, assuming there is no local attraction.

During chaining, a 20 m chain went out of the correct alignment by a perpendicular distance of 1 m. What is the associated error in length measurement in meters?