# MPM1D Pythagorean Theorem 2016-04-18

We started the class with some fraction practice. We’re going to do that from time to time to help improve those skills.

Then we looked at the Pythagorean Theorem. This is a review, but lots of you weren’t familiar with it so we took a little longer than I’d planned.

If you need another explanation, here are a couple you might like:

https://www.mathsisfun.com/pythagoras.html

http://www.purplemath.com/modules/pythagthm.htm

Anyway, we took the “original” formula and rearranged it in a couple of ways:

$h^2 = a^2 + b^2$

$h^2 - b^2 = a^2$

In this form it’s easier to calculate $a$, one of the short sides of the triangle. We then went a step further using the inverse operation to squaring, which is to take a square root:

$\sqrt{h^2 - b^2} = \sqrt{a^2}$

$\sqrt{h^2 - b^2} = a$ since $a \geq 0$ (it’s not negative).

I handed out a page of practice work. You need to finish the front for homework, but not the back (that’s for tomorrow!).