If I understand what kind of answer this question is asking for it should be .12 mile above sea level.
<em>Answer:</em>

<em>Step-by-step explanation:</em>

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<em>by a romanian guy...</em>
If its perimeter, it should be quite easy to find. Just add 12+9+15. Which equals 36. So the perimeter is 36 inches. -Hope it helps!
I think the answer would be 4n
The value of cos A is √(1 + x²)/ (1 - x²) /√1 + x
<h3>Trigonometric ratios</h3>
It is important to note that
sin A = opposite/ hypotenuse
cos A = adjacent/ hypotenuse
Then,
opposite = 
Hypotenuse = 
Let's find the adjacent side using the Pythagorean theroem



cos A = x/hypotenuse

cos A = √(1 + x²)/ (1 - x²) /√1 + x
Thus, the value of cos A is √(1 + x²)/ (1 - x²) /√1 + x
Learn more about trigonometric identities here:
brainly.com/question/7331447
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