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Area

Area is the amount of space taken up by a surface. The areas and perimeters of simple figures such as squares and rectangles can be calculated using formulae. The perimeter of a shape is the total length of all of its sides.

Perimeters are measured using the units of length, i.e. metres.

There are two basic units for measuring area:

• A square metre is the area occupied by a square with each side 1 metre long. It is written as 1 m².
• An are is the area occupied by a square of length 10 m.

Other common units for area are:

Unit	Symbol	Units for measuring:	Conversion
Square centimetre	cm2	Paper, material	10 000 cm2 = 1 m2
Square kilometres	km2	Area of countries	1 km2= 106 m2
Hectare	ha	Land area, e.g. farms	1 ha= 10 000 m2

Area and Perimeter Formulae

Shape	Name	Perimeter	Area
	Square	P= 4 × l = 4l	A = length × width = l2
	Rectangle	P = 2b + 2h	A = base x height = b × h = bh
	Triangle	P = a + b + c	A= half × base × height
	Parallelogram	P = 2b + 2a	A = base × height = bh
	Rhombus	P = Sum of all sides = 4b
	Trapezium	P = Sum of all sides
	Circle	Perimeter is called thecircumference C = 2r = d	A = r2  is a special number approx. 3.1416 (to 4 d.p.) or  or