Answer:
To measure the height of a cell phone tower using trigonometry, we can use trigonometric reasons.
In most of the cases, we recur to the tanget, because it relates the height of the tower cell and the horizontal distance to the tower.

Where
is the angle formed by the ground and the ditance from the grond to the top of the tower,
is the height of the tower and
is the distance between the person and the tower.
The image attached shows the right triangle formed.
So, the tangent reason we use to find the height of the tower.
Using an odometer, we measure the distance of the ground. Using a theodolite we measure the angle
. Then, we use the tangent reason to find
.
That's how we measure the height of the tower.