Heights and distances problems use trigonometry to measure things that are hard or impossible to measure directly — like the height of a building or the distance across a river.
1-A 2-A 3-A 4-A | 5 elevation 6 depression 7 = 60·tan(35°) ≈ 42 m 8 = 120/tan(15°) ≈ 447.8 m 9 = 3·tan(70°) ≈ 8.24 m | 10 = 25·tan(40°) ≈ 20.98 m