Question 1

Paper 1Medium6 marks

A surveyor uses triangulation to estimate the area of a triangular wetland ABCABC Points AA and BB lie on an accessible straight bank, and AB=dAB=d metres. The measured interior angles are ∠BAC=48∘\angle BAC=48^\circ and ∠ABC=67∘\angle ABC=67^\circ

(a)

Find ∠ACB\angle ACB

[1]
(b)

Show that the area TT in m2\text{m}^2 is approximately given by T=0.377d2T=0.377d^2

[2]
(c)

The surveyor wants to map a region with an area of at least 6000 m26000\text{ m}^2 Determine the required value of dd to 3 significant figures. Hence state whether a baseline of 125 m125\text{ m} is sufficient.

[3]

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