What can you use Pythagoras Theorem for in real life?

Question

I know I can use Pythagoras Theorem to calculate the sides of a right triangle.

But so, how and what for the formula can be used in real life? I need some practical examples.

Answer 1

Pythagoras's Theorem is used to compute distances in Euclidean space parametrised with Cartesian co-ordinates.

For many purposes, therefore, it secures the validity of the mathematical model which is used to describe and reason about the "real world" (for some purposes this model is insufficiently accurate and ideas of such as Riemann and Einstein provide models in which Pythagoras does not apply as a universal geometric truth).

This implicit use is more significant than any explicit application in some "real world" example.

Once the validity of the model is established we don't go back to first principles most of the time - people just use the model and take its foundations for granted.

Answer 2

Is a cut corner square? One way to find out with only a ruler is to mark off the point three units away on one side and four units away on the perpendicular side. Then measure between the marks. A square corner = five units.