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A 30-foot tree casts a 12-foot shadow as shown inthe picture.30 ftx12Find the angle of elevation to the nearest tenth.12.850°68.2°90°

A 30-foot tree casts a 12-foot shadow as shown inthe picture.30 ftx12Find the angle-example-1
User Nirmal Prajapat
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1 Answer

21 votes
21 votes

Since the triangle has a right angle, we can conclude that the diagram is of a right triangle.

When dealing with right triangles, there are some useful formulas that are known as 'Trigonometric Identities'. There are a lot of them but we will need only one of those to solve the problem, that's the equation below:


\tan (\theta)=(O)/(A)

Where θ is the angle, O is the length of the opposite side to the angle, and A the adjacent side to the angle.

Therefore, in the case of our problem,


\begin{gathered} \theta=x,O=30ft,A=12ft \\ \Rightarrow\tan (x)=(30)/(12)=2.5 \end{gathered}

Solving for x, we get


x=\tan ^(-1)(2.5)=1.1902\text{rad}

And we can transform radians into degrees,


\Rightarrow x\approx68.2

Thus, the answer is the third option. 68.2°

User Kalimsayyed
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