from a 75ft observation tower a controller sights a hot air ballon at an angle of elevation of 20 degree. if horizontal distance from the tower is 300 feet . what is the elevation of the ballon?

It will be easier to visualize once you draw a figure.

If h is the elevation of the baloon, then, (h-75)/(300)= Tan 20^{0}

Therefore, h-75= 300 tan 20^{0}

So, h= 75 + 300 x tan20^{0}