# trigonometry help please?

here is the question, i have tried it a few times but i cant figure out the right answer, help please:

An observer, whose eyes are 1.77 m above the ground, is standing 27.0 m away from a tree. The ground is level, and the tree is growing perpendicular to it. The observer's line of sight with the treetop makes an angle of 17.0° above the horizontal. How tall is the tree?

### 1 Answer

Relevance

- RackbraneLv 71 decade agoBest Answer
Let:

AB be the tree (A at the top, B on the ground),

CD be the observer (C eye level, D ground),

CE be a horizontal line with E on the tree.

In triangle AEC, angle AEC = 90 deg, angle AEC = 17 deg.

EC = 27.0 m.

AE / EC = tan(AEC)

AE = EC tan(AEC)

= 27.0 tan(17).

The height of the tree is:

AB = AE + EB

= AE + CD

= 27.0 tan(17) + 1.77

= 10.0 m.

Still have questions? Get your answers by asking now.