Trigonometry has applications in a number of scientific fields, ranging from geography and astronomy to engineering and physics. One of the most important early real-life examples of trigonometry involved using the knowledge that the earth was a sphere for navigation. Ptolemy put trigonometry to work in his work "Geography", and Christopher Columbus used trigonometry in finding his way from Spain to what he thought was India but ended up being the New World.
Trigonometry's earliest applications had to do with spheres, but it has had more contributions to work with lanes. Surveyors have long used trigonometry in establishing property lines and boundaries, and military and construction engineers have long used trigonometry in their design and building of projects.
In terms of physics, statics and optics were the first fields to put trigonometry to use, but because trigonometry assists researchers in understanding the way that space works, just about all of the subsidiary fields of physics use trigonometry as well.
Other areas of mathematics also put trigonometry to work. Calculus, statistics, linear algebra and other advanced topics in mathematics rely heavily on trigonometry. It has uses throughout the natural and social sciences. People looking to advance to careers in any of those fields need to have a strong foundation in trigonometry to succeed.