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From a tower 20 m high and 20 m away from a river, the width of the river appears to span an angle of 15°.

How wide is the river at this location?

Final Answer:

w =  14.6 m

Step-by-step explanation:

h=20 m x=20 m α=15° rad=15° 180π =15° 1803.1415926 =0.2618=π/12   tan β = x:h β=arctan(x/h)=arctan(20/20)0.7854 rad γ=α+β=0.2618+0.78541.0472 rad   tan γ = (x+w) : h w=h tanγx=20 tan1.047220=14.6 m



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