In the figure, ABCD represents a large rectangular advertising board - NSC Mathematics - Question 7 - 2016 - Paper 2
Question 7
In the figure, ABCD represents a large rectangular advertising board. A surveyor, standing at the point P, is in the same horizontal plane as the bottom of the uprig... show full transcript
Worked Solution & Example Answer:In the figure, ABCD represents a large rectangular advertising board - NSC Mathematics - Question 7 - 2016 - Paper 2
Step 1
Calculate the length of AB.
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Answer
To find the length of AB, we will use the triangle PMA. Using the sine rule, we can calculate:
Since PM = 10 m and ∠PMA = 35°, we can use the cosine rule:
AB=PM⋅sin(∠PAM)
First, we need to calculate angle PAM:
∠PAM=180°−(∠PMA+∠PMN)=180°−(35°+126.9°)=18.1°
Using that, we calculate:
\approx 10 \cdot 0.310 = 3.10 ext{ m}$$
Therefore, the length of AB is approximately 3.10 m.
Step 2
Calculate how far the surveyor is from the board. (Length of PT)
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Answer
To find the length of PT, we will consider triangle PMT. Here, we have:
PM = 10 m,
MT = AB = 3.10 m,
Using Pythagorean theorem:
PT=PM2−AB2
Thus, we have:
PT=102−3.102≈100−9.61≈90.39≈9.50extm
Therefore, the distance from the surveyor to the board (length of PT) is approximately 9.50 m.