I have very fond memories of high school geometry. Memorizing theorems wasn't too hard, and solving proofs was like solving the logic puzzles that I did for fun anyway. But the theorems were scattered ...

If the sides of the right-angled triangle are labelled 𝑎, 𝑏 and 𝑐 then Pythagoras' theorem can be written as the formula 𝑎² + 𝑏² = 𝑐². Pythagoras' theorem can be used to find the length of line ...