Using HL

When you have a right triangle, consider the Hypotenuse-Leg Theorem.  This video link gives a good example for the last postulate/theorem that we use to prove triangles congruent.  The example shows another way to do proofs - by using flow-chart style proofs.

But, if you prefer the traditional two-colume proof, this video is for you!

Isosceles Triangles

This is a good review of what we learned just prior to the break.  Watch this video to review some of the key concepts in isosceles triangles.  The example that follows is also a challenging practice.

Using AAS

This video link demonstrates the features of the Angle-Angle-Side Theorem.  Of course, there's an example that follows.

Using SSS

One of the easiest postulates to use is the Side-Side-Side Postulate.  This video link gives us a quick overview of what we learned.

Proving Congruent Triangles

The image above sets the beginning stages of this proof.  Try to use our class examples to complete the proof before watching this video.

Parallel Lines Review

This is a slide from our class notes on a lesson in parallel lines.  Make sure you know where the answers are coming from.  Review key terms: linear pair, vertical angles, corresponding angles, same-side interior/exterior angles, and alternate interior/exterior angles.

Classifying Triangles

With the minimum of three sides, triangles are the most basic and important polygons.  Learn the basics and build a strong foundation through classifying triangles.  This skill will help you throughout this and future math classes.  This video serves as a great review.

Exterior Angle-Sum

Here is a link to a good review problem for exterior angles.  You can try it first before watching the video.

Polygon Angle Sum

Try to follow the steps that are provided in the slide to solve the problem.  Then play this video to see if you got the correct answer.  If so, great job!

Exterior Angles

Try the problem that follows the initial instruction of triangle exterior angles.  This skill will help us solve many interesting problems in the upcoming section.

Triangle Sum Theorem

The sum of the three angles in any triangle is 180 degrees.  Any triangle!  They always add up to 180.  Can it be any easier?  = )

Check out this video!  Try the problem at the bottom of the slide.  Post your answer for x, y, and z in the comments section below.  Thanks!

More from Mr. Kennedy

This exciting teacher is at it again! Here is Mr. Kennedy's video on some 3-dimensional geometry concepts. He added some cool animation. Wow, this guy is awesome.

Homework Video Tutorial

This link is to a video for example 2 on page 136, a problem on using parallel lines.  Try to follow along and solve for "x".

Proving Lines Parallel

Proofs are definitely challenging for Geometry students. Here's a video that may help you on your homework!

Starring Mr. Kennedy

Hey, this teacher teaches slightly differently than I do.  He's really awesome.  Check it out.

External Links

On the right margin, you'll see a list of math links.  You are free to explore them.  They can be very helpful towards your homework.  Try A+ Math, it's a site that's colorful and full of games!  Hope you like it.  I'll introduce others throughout the next few days.

Homework Video Tutor

Our textbook's website offers Homework Video Tutorials.  Check this out if you need help with problems from section 3-1.