Composite+Shapes

=Composite Shapes Page:=
 * Activity One: Watch the video**

media type="youtube" key="pcxO9UDT31s" height="315" width="560"

Read the following notes on area
 * Activity Two:**

A figure (or shape) that can be divided into more than one of the basic figures is said to be a **composite figure (or shape)**.
 * [[image:http://www.mathsteacher.com.au/year9/ch14_measurement/11_comp/Image15580.gif caption="external image Image15580.gif"]] ||
 * external image Image15580.gif ||

For example, figure //ABCD// is a composite figure as it consists of two basic figures. That is, a figure is formed by a [| rectangle] and [|triangle] as shown below.
 * [[image:http://www.mathsteacher.com.au/year9/ch14_measurement/11_comp/Image15581.gif caption="external image Image15581.gif"]] ||
 * external image Image15581.gif ||

The [|area] of a composite figure is calculated by dividing the composite figure into basic figures and then using the relevant area [|formula] for each basic figure .

** There are often several ways that the same composite area can be calculated. **

 * [[image:http://y62011.heathfieldcps.net/files/2010/12/Area.jpg caption="Several kids working out of the same sum" link="@http://y62011.heathfieldcps.net/files/2010/12/Area.jpg"]] ||
 * Several kids working out of the same sum ||

Image Source: [|http://y62011.heathfieldcps.net]

It does not matter which way you choose to break the compound shape up, as long as you arrive at the correct answer, and remember to put square units onto the end of the number answer.

Example 20
Find the area of the following composite figure:
 * [[image:http://www.mathsteacher.com.au/year9/ch14_measurement/11_comp/Image15582.gif caption="external image Image15582.gif"]] ||
 * external image Image15582.gif ||

Solution:
The figure can be divided into a rectangle and triangle as shown below.


 * [[image:http://www.mathsteacher.com.au/year9/ch14_measurement/11_comp/Image15586.gif caption="external image Image15586.gif"]] ||
 * external image Image15586.gif ||

So, the area of the composite figure is 216 cm2.

Here is another explanation of how to work out a compound shape from the Learning Pod : Click on the Link: [|Area of Composite Shape]

And this video: media type="youtube" key="pkBSVk2wSSU" height="315" width="420"


 * Activity Three:**

Composite Shapes worksheet. Click on the link and complete the first five pages (three exercises) in your maths books. Write the URL down in your books and complete at home. [|Composite Shapes Worksheets.pdf] (The Answers for this worksheet in meters squared are: 15.76, 15.23, 96.64, 32.14, 44.76, 92.4 ).

=** Remember: **= =** To find areas of composite shapes: **= =** - Split the shape into rectangles, triangles, circles, parallelograms, etc. **= =** - Find the areas all of the individual shapes **= =** - Add or Subtract these areas to get the Total Area. **=