People sometimes describe trigonometry as the science of circles and angles. It's trigonometry that helps you calculate the hypotenuse of a triangle or the diameter of a circle. However, when you use trigonometry in Excel, you probably won't be worrying about shapes; instead, you'll be using some type of formula from a scientific field that requires common trigonometric calculations like the cosine or tangent.

Students of the sciences know that trigonometry turns up anywhere you need to think about space, including geography, astronomy, kinematics, and optics. Less direct applications of trigonometry turn up in just about every other scientific field—from chemistry to social science.