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CPCTC and Circles - Lesson 3-3

We began today by defining some things related to circles and noting a new theorem:

Circle related definitions


We also recalled a couple of (hopefully) familiar formulas and applied them to some example problems:

Ratio of Circumference to Diameter


Example 1


Example 2

We continued by reviewing the definition of congruent triangles and coming up with an acronym for it:


Then we used this, in combination with some of our congruence shortcuts to prove some things!  Now, don't get intimidated by this's really not that hard...and you can all do it!

We started by looking at the following example:

CPCTC Example

which is solved as shown below:

CPCTC Example 1 Answer


We also looked at this one:

CPCTC Example 2 Question

Which is solved like this:

CPCTC Example 2 Answer

We then went on to proofs. Here are two examples using this stuff (note how key the given circle helps to know that the radii from the center are congruent!  Without the fact that the circle is given, the proofs wouldn't be possible!):

Example 3


Example 4

Other Links
Class Notes
Lesson 3-1
Lesson 3-2
Lesson 3-3
Lesson 3-4
Quiz Topics
Lesson 3-5
Lesson 3-6
Lesson 3-7
Lesson 3-8
Test Topics
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