Real world applications of Pythagoras' Theorem I have a school assignment, and it requires me to list a few of the real world applications of Pythagoras Theorem. However, most of the ones I found are rather generic, and not special at all.
What are some of the real world applications of Pythagoras' Theorem?

Say you're playing frisbee with a few of your friends, and the frisbee gets stuck in a tree. You want to get a ladder to reach it, but you don't know how long the ladder needs to be. You can make a point where you want the ladder to touch the ground, and then measure from there, whereas $ds^2=dx^2+dy^2$ is true, so we can say, as an example, that $dx=3 \text{m}$ long and $dy=4\text{m}$ long. Now, we must solve for $ds$. Here's my calculations:
$ds^2=3^2+4^2=9+16=25$
$\sqrt{ds^2}=ds$
$\sqrt{25}=5$
$ds=5\text{m}$
You'd need a ladder that is $5\text{m}$ long to reach the frisbee.
