March 12,2012, Aim: How do we calculate the area of Rectangles and Triangles?

Areas:
-Rectangle:  Base x Height or Length x Width
-Triangle: Base x Height
                        2
Examples:
1) Consider a rectangle of length 5 cm and width 3 cm.

Using the method of counting squares, we find that the area of the rectangle is 15 cm².
Clearly, the rectangle contains 3 rows of 5 squares.  Therefore:

                                        http://www.mathsteacher.com.au/year7/ch13_area/03_rect/rect.htm

2)

	Area = Length x Width Area = 3 x 2 = 6 square units
	Area = Length x Width Area = 8 x 6 = 48 square units

                                              http://www.helpingwithmath.com/by_subject/geometry/geo_area.htm

Now you try it:

1.

 

Find the area.

Choose:

 32.5 sq. units
 400 sq. units 500 sq. units 600 sq. units 

                         Explanation                         Area = (1/2) base times height                         The base is 40.                         The height is 25.                       

                                        http://www.regentsprep.org/Regents/math/ALGEBRA/AS1/PracArea.htm

2.

(a)	Area =  cm²

                                           http://www.cimt.plymouth.ac.uk/projects/mepres/book7/bk7i9/bk7_9i3.htm