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.

Using SAS

Very similar in concept to the ASA Postulate, here is a video link to the description of the Side-Angle-Side Postulate.  Be sure to understand the difference between SAS and ASA.

Using ASA

Here is a video link to the description of Angle-Side-Angle Postulate along with an example.

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.

Constructing Perpendicular Line (part 2)

In this video, we construct a perpendicular line from a point to a line.  See if you can emulate the video with your own drawings.

Constructing Perpendicular Lines (part 1)

One neat use of geometry skills is construction.  Using simply a ruler and compass, you can create some important figures.  Check out this video for one example.

TI-Nspire

One piece of new technology that we have incorporated into our classroom this year is the TI-Nspire calculator.  While it'd be great if all of us have that handheld, for now, the software that I use can help us understand some concepts.  This was a screen shot of the demostration on exterior angles.

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.

Draw a Diagram

This link is to a video with further explanations on how drawing a diagram can help your problem solving skills.  Check it out!

Check for Understanding

Here is a slide that we used to review in class.  See if you can get 10-for-10 this time!

Draw

More so than any other math class, geometry is very visual.  To understand the problem that you are solving, make sure you have a good sketch of the shapes invovled.  Don't be afraid to draw the diagrams yourself and make the proper markings in order to better understand the problem.

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.

Outside the Classroom

Polygons are everywhere.  The one that's most easily recognizable is the octagonal stop sign.  Many gazebos also use octagonal designs.

Heptagon

The seven-sided polygon is rarely studied in geometry.  It's called a heptagon.

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!

Another Example in Sports

The traditional soccer ball is another example using pentagon in sports.  What's the other polygon that is used?  By the way, the soccer ball is also a 3-D example of a sphere.  We'll learn more about spheres next semester.

Example in Sports

The baseball homeplate is a great example of using polygons.  What's the name of this polygon?  Find other examples in sports and comment below.

Real Life Example

The U.S. Department of Defense has a headquarters in Virginia called "The Pentagon", it was built in 1943.  Interestingly, it has five floors above ground and two floors below ground.  You may recall that it was attacked on 9/11.  This link is to their official website.  Can you find other pentagonal shapes in everyday life?

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.

The Louvre Museum

The Lourve Museum is a destination of many Paris tourists.  Check out its interactive website.  The entrance to the museum is a giant glass pyramid made of many triangles.

Pyramids

Slant faces of pyramids are triangular. We'll learn more about 3-D figures in the spring! Can't you find other triangular objects in everyday life?

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!

Real Life Example

As I told you in a previous post, along with other teachers, I am participating in a Wii Bowling tournament to raise money towards a scholarship for a student.  In Wii Tennis, there're many parallel and perpendicular lines.  Can you find them?

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.

Parallel and Perpendicular Lines

Aside from parallel lines, this chapter also deals with relationships involving perpendicular lines.  This is the link to a video explaining some fo the key concepts.

GHS College Bowl

Teachers are raising money towards a scholorship for one special students.  Teams of four teachers are competing in a Wii Bowling Tournament.  The winning team of teachers will decide on the parameters of selecting the recipient.  Here's a picture of me participating.  I'll keep you updated on the results.

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!

From My Dice Collection

A 20-sided die. Icosahedron.  How many vertices does this figure have?

Starring Mr. Kennedy

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

Outside the Classroom

Some of you know that I went to a math conference a few Saturdays ago.  I shared with you some of the neat math gadgets that I brought back.  Here's a picture of the 12-sided dodecahedron that some of you loved so much.  Very Geometric!

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.

Real Life Example

I was watching the Lakers and noticed that the basketball court and the stadium are made up of many pairs of parallel lines. Can you spot them? Post comments on where else you can find parallel lines around you everyday!

Properties of Parallel Lines

We're kicking off this chapter will a new definition - transversal.  It's a line that intersects two lines at two points.  If you haven't, do check out this video: Properties of Parallel Lines.

Let's Begin!

In case you didn't know, our textbook comes with a pretty cool website.  I will add new posts regularly with links to videos.  They will might remind you of lessons we recently did in class!  Enjoy!

(For parents and administrators: This textbook follows the California Content Standards!  Most videos are from our adopted text publisher Pearson Prentice Hall.  Others are from YouTube.com.  Images are from Pearson Prentice Hall.)

Welcome!

Hey Students!  Welcome to our class Weblog.  This will be a place where I will post math related contents for the class.  For the next two weeks (and potentially beyond), we will visit our campus computer lab to investigate the potential of this new learning space.  From here, we can connect ourselves to other web sources to help us learn math!  I will also post interesting pictures for you!

As discussed in class and during our introductory lesson, you are encouraged to check back here as often as possible throughout the break.  You are also strongly encouraged to make comments and ask questions.  Once approved by me, your comments/questions will be posted.  So have fun and I look forward to seeing you here online!

Mr. Yip