Pythagoras’s theorem
Pythagoras’s Theorem is related to right-angled triangles.
Here the sides of the triangle are labelled a, b and h.
The side labelled h is opposite the right-angle.
It is also the longest side.
The h stands for hypotenuse.
The hypotenuse is the longest side of a right-angled triangle.
I don’t know why the word hypotenuse was used for the longest side. The word comes from hypo- meaning under and a word meaning to stretch. To stretch under. You can think of the hypotenuse as the side stretched under the right-angle.
Pythagoras’s Theorem is that, for a right-angled triangle, the length of the hypothenuse squared is equal to the sum of the squares of the lengths of the other two sides.
To write this as a mathematical formula we get:
h² = a² + b²
