Happy Weekend..... Stay Warm!

Math

So far we have been measuring the perimeters of different polygons and determining different polygons with the same perimeter. 

To construct rectangles with similar perimeters, we use our understanding of the relationship between the length and width.

Perimeter of a Rectangle = (Length + Width) x 2

If a rectangle has a perimeter of 18 cm, what are all possible lengths and widths?

If we divide our perimeter in half (by 2) we know the answer will equal the length + width

18 cm divided by 2 = 9 cm

So length + width = 9 cm

What are some possibilities? Think of all the pairs of numbers that add to 9 cm.

8 cm and 1 cm

7 cm and 2 cm

6 cm and 3 cm

5 cm and 4 cm

Can you make a square with a perimeter of 18 cm? You may be tempted to say no because no two numbers add to 9 cm. However, if we include decimal measurements the answer is yes!

4.5 cm and 4.5 cm ( 4 cm and 5 mm or 45 mm)

Try these:

Rectangles with perimeters of 16 cm, 20 cm, 8 m

Grade 5 you should be able to find the side length of any regular polygon if you know the perimeter. For example:

What is the side length of a regular pentagon with a perimeter of 20 cm?

Because it is a regular pentagon, there are 5 equal sides.

Each side will be 20 cm divided by 5 which equals 4 cm.

Review questions for grade 4:

http://math4.nelson.com/quizzes/math4quizzes/m4ch5l5.htm

Review questions for grade 5:

http://www.math5.nelson.com/quizzes/math5quizzes/gr5_ch5_les4.htm

http://www.math5.nelson.com/quizzes/math5quizzes/gr5_ch5_les5.htm

The last set of grade 5 review questions involve a border or frame. See if you can figure them out!

So let's take a look at all the different ways you can find the perimeter of a rectangle:

Perimeter = Length + Length + Width + Width

Perimeter = 2 x Length + 2 x Width

Perimeter = (Length + Width) x 2

Depending on the situation, one equation may be better than another.

What happens to the perimeter when you increase the length by 1?

What happens to the perimeter when you increase the length and the width by 1?

What happens to the perimeter when you increase the length by 1 and decrease the width by 1?

What happens to the perimeter when you double the length?

To find the answers to these questions choose a rectangle and try it!

Have a mentioned this year the importance of proportional reasoning? Hmm.... I think I have ..... a few times.

DON'T FORGET TO FINISH YOUR 

PERIMETER BOOKLET.

Food for thought... Do you agree or disagree? Use an example to support your thinking.

Health

If you can go on line I would strongly recommend finishing your "rainbow" of fruits and vegetables. The computers are not available this week, so you may have to draw your healthy plate, which is fine, but probably not what most of you would prefer to do.

A great day to stay indoors and watch a football game. Go Pats!