What is the importance of trigonometry?
Spherical trigonometry is important because the Earth is a sphere, not a plane, so if you wanted to get the distance between one point on Earth and another, plane trigonometry wouldn't give you the right answer. Plane trigonometry can be used to find the height of something without having to climb it, such as a flagpole or skyscraper. Trigonometry, whether spherical or planar, is used in engineering to design buildings, cars, ships, and planes. It is used in physics to calculate the properties of electric and magnetic fields. It is used in navigation, and projectile motion. It is also used in the design of musical chords and instruments, as well as lenses and optics.