1. 
Horizontal distance \((x)\) :
\(\tan 15˚ =\dfrac{10,000}{x}\)
\(x = \dfrac{10,000}{\tan 15˚}\) so \(x = 37,320.5\) ft.
Distance the plane needs to travel (hypotenuse, \(h\)) :
\(\sin 15^\circ = \dfrac{10,000}{h}\)
\( h = \dfrac{10,000}{\sin 15^\circ}\)
\( h = 38,637.03\)
2. 
\(\tan 12˚ = \dfrac{12,000}{x}\)
\(x = \dfrac{ 12,000}{\tan 12˚}\) or \(x = 56,455.6\) ft
Using the pythagorean theorem, find \(y\): \(y = 57,716.8\) ft
3.
\(\tan 35˚ = \dfrac{x}{25}\)
\(x = 25 \tan 35˚\) ; \(x = 17.5\) ft
But 5.5 needs to be added to it as the angle of elevation was taken from eye height.
The tree is \(23\)ft.