The height of the tree, which Pat needs to determine, before cutting it down to be sure that it will not fall on a nearby fence is 111 ft.
<h3>What is right angle triangle property?</h3>
In a right angle triangle, the ratio of the opposite side to the base side is equal to the tangent angle between them.
![\tan\theta=\dfrac{b}{a}](https://tex.z-dn.net/?f=%5Ctan%5Ctheta%3D%5Cdfrac%7Bb%7D%7Ba%7D)
Here, (b) is the opposite side, (a) is the base side.
Pat needs to determine the height of a tree before cutting it down to be sure that it will not fall on a nearby fence.
The angle of elevation of the tree from one position on a flat path from the tree is
![H=40^o](https://tex.z-dn.net/?f=H%3D40%5Eo)
From a second position,
![I=60\rm\; ft](https://tex.z-dn.net/?f=I%3D60%5Crm%5C%3B%20ft)
Farther along this path it is,
![b=30^o](https://tex.z-dn.net/?f=b%3D30%5Eo)
Let the distance between tree and first position is x. Thus, from the trigonometry,
....1
The distance between tree and second position is (x+60) ft. Thus, again from the trigonometry,
......2
Compare the equation 1 and 2,
![x\tan (40)=(x+60)\tan 30\\0.839x=0.577x+34.64\\0.839x-0.577x=34.64\\x=\dfrac{34.64}{0.262}\\x=132.25\rm\; ft](https://tex.z-dn.net/?f=x%5Ctan%20%2840%29%3D%28x%2B60%29%5Ctan%2030%5C%5C0.839x%3D0.577x%2B34.64%5C%5C0.839x-0.577x%3D34.64%5C%5Cx%3D%5Cdfrac%7B34.64%7D%7B0.262%7D%5C%5Cx%3D132.25%5Crm%5C%3B%20ft)
Put this value in equation 1 as,
![h=(132.25)\times \tan40\\h\approx111\rm\;ft](https://tex.z-dn.net/?f=h%3D%28132.25%29%5Ctimes%20%5Ctan40%5C%5Ch%5Capprox111%5Crm%5C%3Bft)
Thus, the height of the tree, which Pat needs to determine, before cutting it down to be sure that it will not fall on a nearby fence is 111 ft.
Learn more about the right angle triangle property here;
brainly.com/question/22790996
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