Respuesta :

[tex]\quad \huge \quad \quad \boxed{ \tt \:Answer }[/tex]

[tex]\qquad \tt \rightarrow \:Angle \:\: of \:\: elevation= 30° [/tex]

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[tex] \large \tt Solution \: : [/tex]

Let the angle of elevation be " x "

[tex]\qquad \tt \rightarrow \: \cos(x) = \dfrac{9 \sqrt{3} }{18} [/tex]

[tex]\qquad \tt \rightarrow \: \cos(x) = \dfrac{ \sqrt{3} }{2} [/tex]

[tex]\qquad \tt \rightarrow \: x = \cos {}^{ - 1} \bigg( \cfrac{ \sqrt{3} }{2} \bigg ) [/tex]

[tex]\qquad \tt \rightarrow \: x = 30 \degree \: \: or \: \: \cfrac{ \pi}{6} \: \: rad[/tex]

Answered by : ❝ AǫᴜᴀWɪᴢ ❞

Answer:

The angle is 60 degree.

Step-by-step explanation:

First of all, we will find the height if the tree by using Pythagorean theorm.

Let, height of tree be x.

18^2=(9(3^1/2))^2+x^2

324=243+x^2

x^2=324-243

x^2=81

x=9

Now, let the angle be y.

tan y= x/base

tan y=9/9×(3^1/2)

tan y=1.73

y=cot 1.73

y= 60