# Areas and Volume Area is a measure of the surface covered by a given shape Figures with straight sides (polygons) are easy to measure Square centimetres:

## Presentation on theme: "Areas and Volume Area is a measure of the surface covered by a given shape Figures with straight sides (polygons) are easy to measure Square centimetres:"— Presentation transcript:

Areas and Volume Area is a measure of the surface covered by a given shape Figures with straight sides (polygons) are easy to measure Square centimetres: cm 2 Square metres: m 2 Square millimetres: mm 2 Square kilometres: km 2

Areas Imperial units are: Square inch: in 2 Square foot: ft 2 Square yard: yd 2

Area Rectangle and Square: length x breadth Trapezium: Half the sum of the parallel sides x perpendicular height Parallelogram: base x perpendicular height Rhombus (parallelogram with all sides the same length): Half the product of the diagonals or base x perpendicular height

Area Triangle: half the base x perpendicular height http://www.ex.ac.uk/cimt/mepres/book7/bk7i9/bk7_9i5.htm

Area Circle:  r 2  is approximately 3 Many shapes are made up of rectangles, triangles and circles. Calculate each bit.

Volume Rectangle and square: width x base x height Prism - area of cross section x length –e.g. triangular prism is half base x perpendicular height x length –Cylinder =  r 2 x length

Converting Volumes Converting cm 3 to m 3 1m 3 = 100cm x 100cm x 100cm = 1,000,000cm 3 So m 3 expressed in cm 3 should be multiplied by 1 x 10 6

Parts of a Circle A circle is a set of points in a plane that are the same distance from a fixed point (called the centre). These set of points form the perimeter of the circle Circumference (perimeter) The radius is the distance from the centre of the circle to any point on its perimeter. Diameter

Parts of a Circle The name of a line in a circle depends on its position in the circle. A secant is a line that passes through any two points on a circle. A chord is a line that joins two points on the circumference of a circle. The diameter is a chord that passes through the centre of a circle.

Parts of a circle A tangent is a line that touches the circle at only one point An arc is a part of the circumference. A sector is the part of a circle between two radii. A segment is the part of a circle that is between a chord and the circumference A semicircle is a half of a circle.

Parts of a Circle Radius Diameter Secant Diameter Chord Tangent

Parts of a circle SectorSegment

Label the parts of a circle

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