**Solution:**

(a) Draw a line to form a small right-angled triangle next to the angle

Then, you will see that

(vert opp. angles)

(supplementary angles in trapezium)

By sine rule,

(1 d.p.)

(b) By Sine Rule,

(shown)

(c)

By Cosine Rule,

(d)

angle of depression = (1 d.p.)

(e)

Let X be the point where the man is at the shortest distance from D. Draw a right-angle triangle XDC.