3.3 CPCTC and Circles

Today in class we learned about circles and CPCTC, or Corresponding Parts of Congruent Triangles are Congruent. 

First of all, we defined what a circle is. A circle is a set of points that are equidistant from a given point. Also, the circle is just the circumference, or the outside border, and the inside is called the "disk", as shown below:

Secondly, every circle is named by its center point. Again, the circle consists of only the "rim", as the book refers to it, so the center point is not part of the circle. To show the name of the circle, you would draw a small circle with a dot in the middle and then write the letter of the center. (Sorry I couldn't find a good picture of the circle symbol)

Lastly, we learned how to use CPCTC in a proof and that radii imply congruent segments. 

This was basically what we did, except it was obviously one circle, circle O. I couldn't figure out a good way to make the proof (sorry), but we proved that seg. AB was congruent to seg. CD, with CPCTC reason they were congruent. 

That's pretty much what we did in class today!

-Jessica