Changing Area

CHALLENGE QUESTION!

If the area of one figure to another increased 81 times, how many times greater is the perimeter of this new, larger similar figure?

*Hint* Remember the 'rule' we discussed in class.

Perimeter!

Perimeter is the distance around a figure. You can find perimeter by adding all of the side lengths together, or by using a formula. For example, the formula for perimeter of a square is 4s (4 x side length), and the formula for perimeter of a rectangel is 2l + 2w (2 x length + 2 x width). If the shape is irregular, you simply have to add all sides together!

**TRY THIS CHALLENGE QUESTION**
Find the greatest perimeter possible when 6 identical unit squares are arranged to form a closed figure. Adjacent squares (neighboring squares) must share an entire side. You will probably have to draw out six squares and either cut them out or manipulate them on your paper until you find the arrangement with the greatest perimeter :)

Symmetry

Symmetry is everywhere! It's in nature, architecture, shapes, letters, etc.

A figure has line symmetry if it can be folded or reflected so that each of the two parts are congruent. The line of reflection is called the line of symmetry.

Below is an example of symmetry in nature.

source http://farm2.static.flickr.com/1258/813779861_48acd71741.jpg

Symmetry in architecture!

Where do you see symmetry in the world around you?

Triangles

Triangles are tough shapes. They are the most frequently used shape in architecture because they provide such strong support. Triangles cannot be deformed without changing the length of one it's sides or if one of it's joints break.

Notice how the Golden Gate Bridge is constructed with many triangles to give superior strength and durability.

You may not have recognized this, but many bike frames are built using triangles as the primary shape. Mountain bikes and BMX bikes take a lot of beating from their riders during trail riding and trick jumps, but the triangular frame provides the strength needed to support this force!

Share some examples of where you find triangles at use in the world around you. This may be in your home, school, searching on the Interent, etc.

Geometry and Architecture

Hey guys! Branching off of our discussion today, see if you can identify more geometric vocabulary from the video that is linked below.

http://www.thefutureschannel.com/dockets/hands-on_math/abcs_of_architecture/

Click on the link and watch the video. Try to find (visual) and listen (auditory) for the words we discussed in class or any other words that relate to geometry. Leave a comment with your findings! Feel free to watch some of the other videos on how geomtry is used in the world around us :)

Pencil Problem...

Mr. Foster is ordering classroom supplies. He orders enough pencils for every student and then adds 20% more for extras (in case some students lose theirs :). If Mr. Foster has 75 students, what is the total number of pencils he needs to order?

Use the PERCENT PROPORTION to solve this problem. Tell how you set it up and explain the steps for solving:)

Percent Question

If a sales tax rate is 7%, find how much you would have to pay in sales for every $1.00 you spend, for every $10.00 you spend AND for every $100.00 you spend. Give three answers and try to explain how they are related.