Trigonometry is the branch of mathematics that deals with angles and sides of triangles. Trigonometry has many practical uses especially in the surveying, construction, and engineering industries. For the layman, they may not find the need to use trigonometry on a daily basis however if you have knowledge of this type of mathematics and what it can be used for it can make accomplishing many things easier. I'll provide a few examples for my personal life below to show you how trigonometry can be used in everyday life.
My first example has to do with one of my hobbies which involves making props and decorations for plays, movies, and parties. Whenever I am crafting and making these things, I often have to measure things out and cut and shapes and objects to an exact dimension in order to get the look and structural integrity that is needed. In addition, I have to use my tools to make precise angular cuts in a variety of materials in order to maintain the desired level of precision. Instead of trying to measure an angle directly, I can use trigonometric functions to calculate the angles based on lengths of the sides of a triangular instead.
Another time that I use trigonometry is when I was building an addition onto my house. I needed to use trigonometry to calculate the pitch of the roof and the length of the ridge line that I needed in order to maintain the same roof slope on the addition as the house. I made lots of measurements and did some calculations just to be 100% sure of the angles. I took this information to a local truss fabricator who created the trusses that I needed for the home addition.
In addition to these things I also use trigonometry very often in my day job as an engineer.