Hello, matgrl!

This is a classic problem in Trigonometry.

An observer is on the bank of a river at A, opposite a tower TF.

His task is simply to find the height of the tower.

He cannot get to the tower because of the river,

so he has to do this from where he is.

He is equipped only with an inclinometer, a marking pole and a measuring tape.

How can he measure the height of the tower?

Can he still do it with only the marking pole and the measuring tape? . I don't think so. Code:

* T
*/|
* / |
* / |
* / |
* / | h
* / |
* / |
* / |
* β / α |
B * - - - - * - - - - * F
50 A x

The tower is

The observer is at . .Let

He finds that the angle of elevation to the top of the tower is

He walks a distance directly away from the tower, say, 50 feet, to point

At , the angle of elevation to the top of the tower is

In right triangle .[1]

In right triangle .[2]

Equate [1] and [2]: .

. . . . . . . . .

. . . . . .

. . . . . . . . . . .

. . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . .