a) diagram https://ibb.co/v1BxzrW
b) BC = BF - AE = 0.5m
And AC = 2m
So, tan BAC = BC/AC = 0.5/2
or <BAC = tan^-1 (0.5/2) = 14.04 degrees
c) CD = AE- DF = 0.2m
AC = 2m
So, tan DAC = CD /AC = 0.2/2
or <DAC = tan^-1 (0.2/2) = 5.7 degrees
d) diagram: https://ibb.co/d66XYJ8
BC = 0.5 and CD = 0.2 and AC=1
tan BAC = BC/AC = 0.5
<BAC = tan^-1 (0.5) = 26.57 degrees
tan DAC = CD/AC = 0.2
<DAC = tan^-1(0.2) = 11.31 degrees
So the sweeping angle = <BAC + <DAC = 26.57+11.31 = 37.88 degrees