This question was reportedly poorly attempted by majority of the candidates.

In part (a), it was reported that majority of the candidates did not apply the circle theorems correctly. Candidates were expected to show that ∠BCA = 90o. Hence, ∠BCO = 90o – 48o = 42o. Thus, ∠ABC = ∠BCO = 42o (base angles of isosceles triangle BOC).

In part (b), it was reported that candidates’ inability to interpret the question correctly affected their being able to draw the diagram correctly. Some candidates did not draw it at all. As a result, they were unable to apply the trigonometric ratios correctly.

Candidates were expected to draw the diagram thus:

From the diagram, the height of the tower would be h1 + h2 = 50 tan31o + 50 tan25o = 53.36 m.