Perimeter and Area

Students...I am so happy that your homework books have finally arrived!! It has been a long wait, but I know that they will be useful tools for you. Feel free to write inside the books as they now belong to you!!! Just don't lose them!

Just a quick reminder about perimeter and area.

Perimeter is used when you want to find the distance around an object.

Let's take this triangle for example...

I would add up all of the sides of the triangle. (11+9+5=25 cm). The perimeter of this triangle is 25 cm.

Sometimes you run into strange rectangles that look like this...

You have two missing sides that you need to count. The missing sides have to equal what its corresponding side is if its a perfect rectangle. So the missing sides are 8 cm and 3 cm. Add up all of the numbers together (8 + 8 + 3 + 3 = 22 cm). The perimeter is 22 cm.

Area is the number of square units that fit inside a shape. Remember finding out how many cubes could fit on the surface of your desk? Sometimes you have small rectangles that you can easily fill up with cm cubes. Sometimes you have bigger rectangles that it will take a long time to fill up with cm cubes. With big rectangles we multiply (length x width) to figure out how many square units will fit inside.

In this rectangle, the length is 8 cm and the width is 3 cm. I know that 8 x 3 = 24. Therefore 24 cm squared is the area of this rectangle.

Here is a website that will provide additonal practice if you want to extend your skills.

http://www.mathgoodies.com/lessons/toc_vol1.html