Pythagorean Theorem
My favorite math theorem would be Pythagorean Theorem. It's simple and easy to use. It's one of the most basic theorem that we need to know in Mathematics.
Basically the theorem say the square of the hypotenuse equals to the sum of the other two sides of a right triangle (90 degrees).
$ p^2 = q^2 + r^2 $ where,
p: hypotenuse
q & r: the two sides of the right triangle
This easy and useful theorem is regularly use to solve many mathematics problems especially the topics that involve angles and so on.
