NumericalModerate2 marks
6(ii)
In the given diagram, AB is a vertical tower 100 m away from the foot of a 30 storied building CD. The angles of depression from the point C and E, (E being the mid-point of CD), are 35° and 14° respectively. (Use mathematical table for the required values rounded off correct to two places of decimals only.) Find the height of the:
building CD
Topic: Heights and distances
Previous-year question practice database
Answer
Exam answer
From: H−h = 70 and H/2−h = 25,
subtracting gives: H/2 = 45 H = 90 m.
Answer: Building CD = 90 m.
Explanation
E is the midpoint of CD, so ED = H/2. The same two tangent equations from part (a) determine the full building height.
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