 Socotower, Pythagoras, Sine rule and cosine rule and all things trigonometry actually have a lot of uses in real life such as working out distances to things and heights of buildings and mountains and navigation at sea. An important part of useful trigonometry are angles of elevation and depression. If you're standing and looking up at an object, the angle from your horizontal line of sight up to the object is the angle of elevation, whereas if you're looking down at an object, the angle between your horizontal sight line and the object is known as the angle of depression. Be careful to remember that this is the angle of depression and not this. It's a common mistake to make. We then use all of our trigonometry skills to solve problems involving angles of elevation and angles of depression. Let's look at some examples. Next time you're out and about, stand 10 metres away from a building. Guestimate the angle of elevation from your sight line to the top of the building. You can now use Sokotoa to work out the actual height of the building. And remember to add on your height to get the correct answer. Here are some questions for you to do. Pause the video, whack them out and click play when you're ready. Did you get 520 metres? Did you spot that the angle of depression is here and so the angle in the triangle is actually 60 degrees and 1143 metres for the plane. So there we have some real world uses of trigonometry involving angles of elevation and angles of depression. If you liked the video, give it a thumbs up and don't forget to subscribe, comment below if you have any questions. Why not check out our Fusical app as well? Until next time.