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YEAR 4 <ul><li>Curriculum Specifications: </li></ul><ul><li>9.0 Shape and Space </li></ul><ul><li>9.1 Two dimensional shapes </li></ul><ul><li>9.1.1 Understand the perimeter of a two-dimensional </li></ul><ul><li>shape. (square, rectangle and triangle) </li></ul><ul><li>9.1.2 Understand the areas of a two-dimensional shape </li></ul><ul><li>(square and rectangle) </li></ul><ul><li>9.1.3 Find the area and perimeter. </li></ul><ul><li>9.2 Three-dimensional shapes </li></ul><ul><li>9.2.1 Understand the volume for cubes and cuboids. </li></ul><ul><li>9.2.2 Find the volume for cubes and cuboids. </li></ul>
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Two- dimensional geometric forms rectangle square rhombus triangle hexagon circle Examples:
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Two- dimensional geometric forms <ul><li>These geometric figures have only two dimensional plane surfaces </li></ul><ul><li>- length </li></ul><ul><li>- breadth </li></ul>length breadth
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Three- dimensional geometric forms <ul><li>These geometric figures are solid forms which have three dimensions </li></ul><ul><li>- length </li></ul><ul><li>- breadth </li></ul><ul><li>- height </li></ul>length breadth height
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Perimeter <ul><li>Perimeter is measurement of length of a boundary </li></ul><ul><li>which encompasses a closed plane surface . It is the </li></ul><ul><li>distance around the outside edge of a figure. </li></ul><ul><li>In Mathematics, perimeter is the total length of the </li></ul><ul><li>sides enclosing a certain geometrical shape. </li></ul>10cm 10cm 4cm 4cm Perimeter = 10cm + 4cm + 10cm + 4cm = 28cm OR Perimeter = 10cm × 2 + 4cm × 2 = 20cm + 8cm = 28cm
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Try out the questions below. Important steps should be shown in your task sheet given. 1) 75cm 182cm 163 cm What is the perimeter of the triangle above?
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2) 68cm 154cm What is the perimeter of the rectangle above? 3) What is the perimeter of the equilateral triangle above? 57cm
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4) The perimeter of the square above is 148cm. What is the length of its side? 5) 195cm The perimeter of the rectangle above is 534cm. What is the length of BC? B C A D
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Area <ul><li>Area is the amount of space or surface which occupies </li></ul><ul><li>a two-dimensional closed plane figure. </li></ul>A = length × breadth rectangle A = length × length square Area Formulae Two-dimensional geometric figures Names
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simple concept about area C B A D The rectangular board is divided with squares of unit size each. We can find the area of any part by counting the number of squares as its unit measure. Thus, Area of A = 2 square units or 2 unit ² Area of B = 3 square units or 3 unit² Area of C = 4 square units or 4 unit² Area of D = 5 square units or 5 unit²
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Try out the questions below. Important steps should be shown in the task sheet given. 1) <ul><li>What is the length of the square above? _____cm </li></ul><ul><li>b) What is the perimeter of the square above? _____ cm </li></ul><ul><li>c) What is the area of the square above? ______ cm ² </li></ul>2cm 2cm
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2) 3cm 3cm a) What is the length of the rectangular above? _____cm b) What is the perimeter of the rectangular above? _____cm c) What is the area of the rectangular above? _____cm ²
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3) The area of a rectangle is 120cm². If the breadth is 5cm, what is the length? 4) The length of a carpet is 12m. Its breadth is less than the length by 4m. What is the area of the carpet? 5) The area of Ahmad’s school field is 6000m². If the length is 100m, what is the breadth of the field?
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Volume <ul><li>The real world is actually a three-dimensional </li></ul><ul><li>space. All things in this world, whether solid, liquid </li></ul><ul><li>or gaseous, exist in three dimensions. As such, the </li></ul><ul><li>amount of three-dimensional space which an object </li></ul><ul><li>occupies is called its volume. </li></ul><ul><li>To calculate the volume of an object or solid, we </li></ul><ul><li>have to use a specific unit of measure. </li></ul><ul><li>The most suitable shape for the unit of volume is a </li></ul><ul><li>unit cube with dimensions 1cm × 1cm × 1cm. </li></ul>
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A unit cube is a cube whose edges are of unit length. The volume of a unit cube with edges 1cm each is 1cm × 1cm × 1cm = 1cm ³ This unit cube is the unit of measure usually used for measuring volume of a solid. 1cm 1cm 1cm Example: If = 1cm³, find the volume of the solid below. Solution: Volume = 1cm³ × 4 = 4cm³
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Volume of cube = length × 3 = l ³ Volume of cuboid = length × breadth × height OR Volume of cuboid = Area of base × height l l l l b h
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Try out these questions. Important steps should be shown in the task sheet given. <ul><li>Siti has a shoe box. Find the volume of the shoe box if its length is 40cm, its breadth is 20cm and its height is 10cm. </li></ul>2) The volume of a cuboid is 1120cm ³. Its breadth is 8cm. Its height is 7cm. What is its length?
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3) The milk container is a cube. What is the length of its side? Milk 1000cm ³ 4) The volume of the pencil case is 720cm ³. What is its length? Pencil case 5cm 8cm
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5) The length of the cube is 4cm. The area of the cuboid is 27cm ² What is the total volume of the cube and cuboid? 5cm
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What did we learnt here? 2D Shapes 3D Shapes Perimeter Area Volume