Answers

2015-01-22T20:35:53+08:00
Triangle
Area = ½ × b × h
b = base
h = vertical height
 Square
Area = a2
a = length of side
Rectangle
Area = w × h
w = width
h = height
 Parallelogram
Area = b × h
b = base
h = vertical height
Trapezoid (US)
Trapezium (UK)
Area = ½(a+b) × h
h = vertical height
 Circle 
Area = π × r2 
Circumference = 2 × π × r
r = radius
Ellipse
Area = πab
 Sector
Area = ½ × r2 × θ 
r = radius
θ = angle in radians
Note: h is at right angles to b: 

 

Example: What is the area of this rectangle?The formula is:Area = w × h
w = width
h = heightWe know w = 5 and h = 3, so:Area = 5 × 3 = 15
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2015-01-23T13:33:48+08:00
Square
Side= 5 cm
A square= SxS
A square= 5cm x 5cm
A square= 25cm raise to 2
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