Maths

• Units of length


  • kilometre (km)
  • metre (m)
  • centimetre (cm)
  • millimetre (mm)
• Perimeter


  The distance around a closed shape
• All units must be of the same type when calculating the perimeter
• Sides with the same type of markings (dashes) are of equal length
• Convert lengths to units shown in brackets


  1. Identify the given length and the target unit

  2. Convert the length to the target unit
• Convert lengths to units shown in brackets

  • 5.2 cm (mm)
  • 85,000 cm (km)
• Find the perimeter of a shape


  1. Identify the lengths of all sides

  2. Add up the lengths of all sides
• Find the perimeter of a shape


  • Example 2
• Find the unknown value x in a triangle

  1. Identify the given side lengths

  2. Use the perimeter formula to solve for x
• Find the unknown value x in a triangle


  • Example 3
• Diameter


  The distance across the centre of a circle
• Radius


  The distance from the centre to the circle
• Radius = 1/2 Diameter
• Circumference


  The distance around a circle
• Pi (π)


  ≈ 3.14159 (correct to five decimal places)
• Find the circumference of a circle

  1. Use the formula: C = π × d (where d is the diameter)

  2. Use the formula: C = 2 × π × r (where r is the radius)
• Find the circumference of these circles, correct to two decimal places


  • Diameter = 10cm
  • Radius = 7cm
• Calculate the circumference of these circles using the given approximation of π


  • Diameter = 20cm
  • Radius = 14cm
• Find the perimeter of a semicircle


  Use the formula: Perimeter = Diameter + π × Radius
• Common metric units for area


  • square millimetres
  • square centimetres
  • square metres
  • square kilometres
  • hectares
• Basic shapes for area calculation

  • Square
  • Rectangle
  • Parallelogram
  • Triangle
• Areas of composite shapes can be found by adding or subtracting the area of more basic shapes
• Convert area measurements to units shown


  • 0.248 (square metres)
  • 3100 (square centimetres)
• Convert area measurements to units shown


  • 3.51 (square kilometres)
  • 150 (square metres)
• Find the area of basic shapes

  • Square
  • Rectangle
  • Parallelogram
• Homework


  • Textbook Questions
  • Extension
  • Challenge
  • Exercise 4B p.237
  • Q2-4, 6, 7
  • Q8
  • Q9
• Find the area of composite shapes using addition or subtraction


  • Composite shape
  • Composite shape
• Special quadrilaterals for area calculation

  • Rhombus or Kite
  • Trapezium
• Find the area of special quadrilaterals

  • Rhombus/Kite
  • Trapezium
  • Rhombus/Kite
• Area of a Circle

  The ratio of the area of a circle to the square of its radius is equal to π
• Radius


  Can be found from the Area
• Pi (π)


  ≈ 3.14159 (correct to five decimal places)
• Semicircle


  A half circle
• Quadrant


  A quarter circle
• Example 1


  • Use a calculator to find the area of this circle, correct to two decimal places
  • Use a calculator for the value of π
• Example 2


  • Find the area of these circles using the given approximation of π
• Example 3


  • Find the area of this quadrant and semicircle, correct to two decimal places
  • Use a calculator for the value of π
• Homework


  • Textbook Questions
  • Extension
  • Challenge
• Exercise 4E p.258