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The problem reads:
At a certain point in a large, level park, the angle of elevation to the top of an office building is 30 degrees. If you move 400ft closer, the angle of elevation is 45 degrees. To the nearest 10 ft, how tall is the building?

I tried to solve it myself, but I couldn't find the adjacent measurement of 45 degrees. Please explain how to solve this problem. Thanks you!
 Mar 5, 2014
 #1
avatar+6251 
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Quote:

At a certain point in a large, level park, the angle of elevation to the top of an office building is 30 degrees. If you move 400ft closer, the angle of elevation is 45 degrees. To the nearest 10 ft, how tall is the building?



tan(30) = H/D = sqrt(3)/3
H = D * sqrt(3)/3

tan(45) = H/(D-400) = 1
D-400 = H

D-400 = D * sqrt(3)/3
D(1 - sqrt(3)/3) = 400

D = 400/(1 - sqrt(3)/3)) = 946.41
H = D - 400 = 546.41
 Mar 6, 2014
 #2
avatar+118667 
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williamfartsabomb:

The problem reads:
At a certain point in a large, level park, the angle of elevation to the top of an office building is 30 degrees. If you move 400ft closer, the angle of elevation is 45 degrees. To the nearest 10 ft, how tall is the building?

I tried to solve it myself, but I couldn't find the adjacent measurement of 45 degrees. Please explain how to solve this problem. Thanks you!



You beat me to it Rom.
I was just off drawing my own picture.
I'll have to be quicker off the mark next time.
oh well, can't let it go to waste.
I was going to use the sine rule to find y
And then either sin or cos or pythagoras to find x.

140306 Trig elevation .JPG
 Mar 6, 2014

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