Hi!
To find the semmetry between the nonagon just do this:
360 / 9 = 40
The regular nonagon has rotational symmetry of 40 degrees!
59.96.
If you distribute 4 to 14.99 then you get the answer above.
Draw a right triangle to represent the problem.
The vertical height of the triangle is 9 ft, and it represents the tree.
The horizontal length, at the bottom of the tree is ground level and has a length of 13 ft.
Let x = angle of elevation.
By definition,
tan x = 9/13 = 0.6923
x = arctan(0.6923) = 34.7 deg. = 35 deg (approx)
Answer: 35°
The answer should be 30. I hope this helps :)
