Question

A man standing on level ground is 1000 feet away from the base of a 350-foot-tall building. Find,

Answer 1

If you sketch the man and the building on paper, you'll have a
right triangle.  The right angle is the point where the wall of
the building meets the ground.  The height of the building
is one leg of the triangle, the line on the ground from the
building to the man's feet is the other leg, and the line
from his feet to the top of the building is the hypotenuse.

We need to find the angle at his feet, between the hypotenuse
and the leg of the triangle.

Well, the side opposite the angle is the height of the building -- 350ft,
and the side adjacent to the angle is the distance from him to the
building -- 1,000 ft.

The tangent of the angle is      (opposite) / (adjacent)

                                                = (350 ft)  /  (1,000 ft) = 0.350 .

To find the angle, use a book, a slide rule, a Curta, or a calculator
to find the angle whose tangent is 0.350 .

           tan⁻¹(0.350)  =  19.29° .  (rounded)