Presentation on theme: "Area - Revision The area of a shape is simply defined by : “the amount of space a shape takes up.” Think of a square measuring 1 cm by 1cm we say it is."— Presentation transcript:
Area - Revision The area of a shape is simply defined by : “the amount of space a shape takes up.” Think of a square measuring 1 cm by 1cm we say it is : 1cm 1cm 2 ( 1 square centimetre )
Area of a Rectangle Example Find the area of the rectangle L = 9cm B = 2cm Area = Length x Breadth A = L x B A = 9 x 2 A = 18 cm 2
Area of a Rectangle Example Find the length B of the rectangle opposite L = 12cm B cm Area = Length x Breadth A = L x B 36 = 12 x B Balancing Method A = 36cm 2 Remember units
Calculate the area of this shape 8cm 9cm 5cm 6cm A = l x b A = 9 x 8 A = 72cm 2 A = l x b A = 6 x 5 A = 30cm 2 Total Area = = 102cm 2 72 + 30 Area of a Composite
Calculate the area of this shape 5cm 6cm 16cm 5cm A = l x b A = 16 x 5 A = 80cm 2 Rectangle 1 Rectangle 2 A = l x b A = 6 x 5 A = 30cm 2 A = 30cm 2 Total Area = 80 + 30 =110cm 2 Area of a Composite
6 Any Triangle Area h b Sometimes called the altitude h = vertical height
7 Any Triangle Area 6cm 8cm Example 1 : Find the area of the triangle.
Any Triangle Area 10cm 4cm Example 2 : Find the area of the triangle. Altitude h outside triangle this time.
Parallelogram Area b Important NOTE h = vertical height h
Example 1 : Find the area of parallelogram. 9cm 3cm
Area of a Rhombus D d This part of the rhombus is half of the small rectangle.
Area of a Kite D d Exactly the same process as the rhombus
Rhombus and Kite Area Example 1 : Find the area of the shapes. 5cm 2cm 9cm 4cm
Trapezium Area W X Y Z 1 2 a cm b cm h cm Two triangles WXY and WYZ
Trapezium Area Example 1 : Find the area of the trapezium. 6cm 4cm 5cm
Parts of the Circle Circumference O O = centre of circle The radius is measured from the centre of the circle to the edge. radius diameter The diameter is measured from one edge to the other passing through the centre of the circle. Radius = ½ x diameter Diameter = 2 x radius
Circle Investigation To calculate the circumference of a circle
Main part of a Circle 10cm 2cm Example : Find the length of the circumference (Perimeter) of each circle
Area of a Circle To find the area of a circle A = Πr² Where A = area r = radius
Area of a circle Q.Find the area of the circle ?Solution 4cm
Area of a circle Q. The diameter of the circle is 60cm. Find area of the circle?Solution