Angle of Elevation and slope 
Standing on top of a gentle 5degree slope I see the top of a tall building at an angle of elevation of 35degree 15’.  I am 160 cm tall and it is 12 m from where I am standing to the foot of the building. 
Calculate how tall the building is? 

Use trigonometry after drawing lines parallel to the ground from the foot and head of the person.
$Building Height=12\sin5^{\circ}+1.6+12\cos5^{\circ}\tan35^{\circ}15'$
Your answer is about 6.79686689258 meters.
