Wednesday, April 15, 2009

Wednesday, April 15th, 2009

1. Warm-up: Read pages 572 to pages 574 in the textbook.

2. Using activestudio, do investigations 1, 2 and 3 on page 572 to 574. Fill in the conjectures:

AA Similarity Conjecture: If ____________ angles of one triangle are congruent to ___________ angles of another triangle, then _________________.

SSS Similarity Conjecture: If the three sides of one triangle are proportional to the three sides of another triangle, then the two triangles are _____________________.

SAS Similarity Conjecture: If two sides of one triangle are proportional to two sides of another triangle and ______________, then the ______________________.

Shanice B. in first period was the first student to answer conjecture C-93 at the conclusion of investigation 1. Good job Shanice!

Do problems 1-15 on page 575 odd. 1-15 even is homework.





Tuesday, April 15th, 2009


No laptops today, but the lesson went well in all classes. Each class came up with their own definitions of similar polygons:

1. "They have the same number of sides."
2. "They have the same shape."
3. "One is bigger, one is smaller."
4. "It doesn't matter if they are spun or flipped."
5. "All the angles have to be the same."
6. I then had to give everyone the following point:
"The sides will be in proportion to one another."

To see this, measure any two sides on one hexagon and divide, then measure the same two corresponding sides on the other hexagon and divide, you will get the same value. Now we see why we did all that algebra during Monday's class.

Homework due Wednesday morning is 10-14 on page 568 to page 569.

NOT ENOUGH STUDENTS DID THE HOMEWORK DUE THIS MORNING! We are back in the full swing of things, spring break is over! Let's get to work! Benchmarks test again in May!

Monday, April 13, 2009

Monday, April 13th, 2009


In class today we covered pages 560 and 561. Homework was 561 problems 2-12 even.

Wednesday, April 1, 2009

April 1st, 2009

1. Test tomorrow! Get ready! The number one thing you will need to remember for the test is that if you have a quadratic equation with real coefficients and a negative discriminate then the roots will be imaginary conjugates. The second thing you will need to know is today's date.

2. The formula for the volume of a sphere is V=(4/3)πr^3. Watch this video.

3. The formula for the surface area of a sphere is A=4πr^2. Watch this video.

4. Now explore this applet.

5. Now solve problems 1 through 6 on page 547 to 548. Homework is problems 7, 8 and 9.

6. Some of you may ask the question, how do we know that these formulas are true. Our textbook Discovering Geometry relies upon experimentation to show that these formulas are true. But there is another way, see here.