From an airplane at an altitude of 1200m the angle of depression to a building one the ground measures 28 degrees. find the distance from the plane to the building

Check the picture below.

now, we're assuming "to the building" means "to the ground", since we don't know the building's height, so we're also assuming the 1200m is above the building, as you see in the picture.

make sure your calculator is in Degree mode.

answer:  

step-by-step explanation:

here x represents the height of the pole,

and, the height of the shadow of the pole is 12 feet.

also, the angle of elevation from the top of the pole is 40°,

therefore,

by the low of sine,

which is the required equation for finding the value of x,