Chapter 9: The Distance Formula

Chapter 9: The Distance Formula

Hey guys, it's Robbie. Today in class we reviewed the distance formula.

One of the semi-new things we learned about the distance formula is that it comes directly from the Pythagorean Theorem.

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

Here is a link to a website that shows how this is. Basically, a right triangle is drawn with the legs falling on the lines of the coordinate plane. Then you can use the Pythagorean Theorem t o find the length of the hypotenuse. Using the distance formula on the

same triangle, you'll find that the Distance simplifies down to the the Pythagorean Theorem.

Ok, so the distance formula is:

So:

So, for example, you want to find the distance between (-4,5) and (-2,-1).

You do √(-2+4)² + (-1-5)². So that simplifies to √ 4+ 36 which simplifies to √40. This is pretty common with the Distance Formula. It results in a square root value a good number of times. To finish the example off √40 finally simplifies to 2 √10.

So, yeah, thats all we learned about today in class. Wasn't too difficult and mostly a review.

Robbie

P.S. The reason this is posted under Michael's account is because my account was not letting me post so I borrowed his.

P.S.S For those of you who play this, you lose the game