I don't know how to put in a square root symbol here so know that it is over h.

The equation D=1.2 square root h gives the distance D in miles that a person can see to the horizon from a height h in feet. Solve for h. Do I find the square root of 1.2?

5 answers

yes.
Ignore the previous answer.

According to your formula, you find the square root of h (in feet) and multiply it by 1.2. The answer will be in miles.

A more correct factor to use is 1.23.
To determine how far in miles we can see from a building of height h ft., we use d = sqrt[1.5h].
To determine the height of a building we can see from a distance d off shore, we use h = sqrt(r^2 + d^2) - r, r and d in feet.

r = the radius of the earth in feet
d = the distance off shore in feet
h = the height of the building in feet.
so- D/1.2=the square root h

Long's Peak in the rocky mountains is 14,255 feet I need to get the number of miles 5280 or 2.7 miles? then divide that by 1.2 or 2.25 miles?
In the case of Long's Peak, using the formula you have been given, take the sqrt of 14255, multiply it by 1.2, and you will have the answer in miles for the distance d that you can see to the horizon. I get 143 miles. That's about to the next state, if you are looking east (Kansas)