Ellipsoidal trigonometry

Ellipsoidal trigonometry is a way to measure angles and distances on the Earth's surface using an "imaginary" shape called an ellipsoid.

An ellipsoid is a squished sphere. It's not a perfect sphere, but it's close enough to be useful for measuring things on the Earth's surface.

Think of a ball that's been squeezed a little bit on each end - it's not quite round anymore, but it's still pretty close.

Ellipsoidal trigonometry allows us to measure angles and distances between points on the ellipsoid, which is a closer approximation of the Earth's shape than a perfect sphere.

This is useful for things like mapping and navigation, where we need to know exactly where we are and how to get to a specific destination.

So, when people use ellipsoidal trigonometry, they're essentially using a math system that helps them measure angles and distances on a shape that's more like the actual shape of the Earth.