From top of building, depression of top and bottom of p... – Trigonometry

Trigonometryhard · Past Paper

From top of building, depression of top and bottom of pole are 30 and 45. If pole is 10 m, building is:

A5(3+√3) m

B10√3 m

C20 m

D15 m

✓ Correct Answer: A — 5(3+√3) m

h/d = tan 45 = 1 => h=d. (h-10)/d = tan 30 = 1/√3. h-10 = h/√3. h(1 - 1/√3) = 10. h = 10√3 / (√3-1) = 5(3+√3).

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