You are lying 120ft away from a tree that is 50feet tall .you look up at the top of the tree . approximately how far is ur head from the top of the tree. in straight line

If you picture this scenario in your mind, you can see that yourself and the tree form a right triangle. Therefore, you can use Pythagoras' Theorem to find the distance between your head and the top of the tree.
a² + b² = c²
50² + 120² = c²
2500 + 14400 = 16900
√16900 = 130
So your answer is 130ft. I hope this helps!