Maths Made Easy Forums Standard Trigonometry Bearings – Right Trig

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• #13817
Keymaster
Post count: 802

The true bearing of P from Q is:

a.   080°   b.   100°   c.   280°   d.   W80°N

Since the bearing is P FROM Q, then we must look at the point Q
Subtract 80° from 360° to get 280°, remembering that true bearings work clockwise from north
hence C is the correct answer

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Keymaster
Post count: 802

A man travels 20km in the direction 330°. How far has he travelled?

This is a trick question and needs to be read carefully. A man travels 20km in the direction 330. How far has he travelled? 20km There is nothing to actually work out, it says how far he has travelled, and it asks how far he has travelled.

Keymaster
Post count: 802

A  man starts from X and walks 2km N35°W to Y, and then turns to his right, through 90°, and walks 1km to Z.  What is the direction of Z from X?

$$\tan\theta=\frac{1}{2}$$

θ = 27°

the direction from North will be 35° – θ
= 35° – 27°
= 8°

∴ the direction will be N8°W

Keymaster
Post count: 802

A yacht sails due west for 45 nautical miles, before turning north for 23 nautical miles.
a. Calculate the bearing of the yacht from its starting point
b. On what bearing must the yacht sail to return to its starting point.

a. $$\tan x=\frac{23}{45}$$
x = 27°
∴ bearing= 270° + 27°     (remembering that it is 270° around from north to west)
= 297°

b.  y = 180° – 90° – 27°  (angle sum of Δ = 180°)
y = 63°

∴ bearing= 180° – 63°
= 117°