Formulae for Finding the Area of the Rectangle, Triangle, Parallelogram and Trapezium

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Wednesday, 28 October 2009
Formulae for Finding the Area of the Rectangle,
Triangle, Parallelogram and Trapezium
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The Rectangle Area 4 x 3 Area 12 square
units Area 12 units2
3
4
Height
Base
Area Base x Height A BH
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From Rectangles to Triangles
Height
Base
Base
Notice that a rectangle contains 2
triangles Area Base x Height 2 A
BH 2 (or) ½ BH
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Triangle
Height
Base
Base
Area Base X Height 2 A BH/2 (OR) ½BH A
8 X 12 2 A 48 cm2
Height is12cm Base is 8 cm
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Parallelogram
Height
Base
Area Base x Height A BH
6
Height
Base
7
Trapezium
b
a
c
Area a x (b c) 2